|
Tutors Answer Your Questions about Rate-of-work-word-problems (FREE)
Question 572099: A farmer drives a tractor from one town to another, a distance of 130 kilometers. He drives 9 kilometers per hour faster on the return trip, cutting 1 hour off the time. How fast does he drive each way?
Answer by nyc_function(2645)   (Show Source):
You can put this solution on YOUR website!I like faxing my answers to math questions. If you have a fax number, I will write my reply on paper and then fax the answer to you showing all the needed steps. If you need the answer right now, then please repost your question for others to see and reply.
Question 571472: A swimming pool can be filled up by pipes A and B in 3 hours and 35 minuted. If pipe A can fill the pool in 6 1/2 hours, how long can pipe B fill it alone?
Answer by ankor@dixie-net.com(12701)  (Show Source):
You can put this solution on YOUR website!A swimming pool can be filled up by pipes A and B in 3 hours and 35 minutes.
If pipe A can fill the pool in 6 1/2 hours, how long can pipe B fill it alone?
:
We can do this in minutes, avoid those annoying fractions, then convert the answer back to hrs and min.
3(60) + 35 = 215 min
6(60) + 30 = 390 min
:
Let B = time for pipe B to fill it alone
Let the completed job = 1; (a full pool)
:
A typical shared work equation
 +  = 1
multiply by 390B
390B* + 390B* = 390B
cancel the denominators and you have
215B + 390(215) = 390B
83850 = 390B - 215B
83850 = 175B
B = 
B = 479.143 minutes
:
Convert to hrs and min, divide by 60; mult the decimal portion times 60
7 + .986(60) = 7 hrs 59 minutes for B to the job
Question 571266: A swimmming pool can be filled up by pipes A and B in 3 hours and 35 minutes. If pipe A can fill the pool in 6 1/2 hours, how long can pipe B fill it alone?
Answer by lwsshak3(2927) (Show Source):
You can put this solution on YOUR website!A swimmming pool can be filled up by pipes A and B in 3 hours and 35 minutes. If pipe A can fill the pool in 6 1/2 hours, how long can pipe B fill it alone?
**
3hrs and 35 min=215 min
6 1/2 hrs=390 min
let x=minutes pipe B can fill the pool alone
..
sum of individual work rates=work rate working together
1/390+1/x=1/215
1/x=1/215-1/390
1/x=(390-215)/215*390=
1/x=175/83850
x≈479 min
Question 571268: Mary can finish an embroidery work in 10 days. After working for 3 days, Mary's cousin joined and together they finished the embroidery in another 4 1/2 days. How many days can Mary's cousin finish the work alone?
Answer by scott8148(5891)  (Show Source):
Question 571269: How much water should I evaporate from 10 liters of 3% salt solution if I want a solution containing 5% salt?
Answer by scott8148(5891) (Show Source):
Question 571158: Susan delivers 108 newspapers in 90 minutes. Stan delivers the same number of newspaper 120 minutes. which of the following formula would allow you to determine the time required to deliver the newspapers by both Susan and Stan working together
Answer by lwsshak3(2927) (Show Source):
You can put this solution on YOUR website!Susan delivers 108 newspapers in 90 minutes. Stan delivers the same number of newspaper 120 minutes. which of the following formula would allow you to determine the time required to deliver the newspapers by both Susan and Stan working together
**
let x=minutes required by Susan and Stan working together to deliver the newspapers
Susan's work rate=108/90
Stan's work rate=108/120
working together Susan and Stan can deliver 108 newspapers in x minutes
108x/90+108x/120=108
LCD: 90*120
120*108x+90*108x=90*120*108
120x+90x=90*120
210x=10800
x≈51 minutes
Question 571098: 8 men can dig 168 ft in 7 hours, 3 men can backfill 120 ft in 4 hours; in how many hours can 5 men can dig and backfill 300 ft.?
Answer by stanbon(48558) (Show Source):
You can put this solution on YOUR website!8 men can dig 168 ft in 7 hours, 3 men can backfill 120 ft in 4 hours; in how many hours can 5 men can dig and backfill 300 ft.?
-----
time is indirectly related to # of men and directly related to dig-distance.
---------------------
t = k*d/n
-----
Solve for "k" using "8 men can dig 168 ft in 7 hrs".
7 = k*168/8
k = (8*7)/168 = 1/3
Dig Equation: t = (1/3)d/n
---------------------------
3 men can backfill 120 ft in 4 hours
time is directly related to fill-distance and indirectly related to # of men.
t = k*d/n
----
Solve for "k":
4 = k*120/3
k = 12/120
k = 1/10
Fill Equation: t = (1/10)d/n
---------------------
Question: in how many hours can 5 men can dig and backfill 300 ft.?
Dig: t = (1/3)300/5 = 20 hrs
Fill: t = (1/10)300/5 = 6 hrs
---
Total time: 26 hrs
=================================
Cheers,
Stan H.
===========================
t
Question 571033: A square vegetable garden is to be tilled and then enclosed with a fence. If the fence costs $2.50 per foot and the cost of preparing the soil is $0.60 per ft2, determine the size of the garden that can be enclosed for $257.60.
Answer by josmiceli(6786)  (Show Source):
Question 570872: Two cylindrical cans have the same volume. The height of one can is triple the height of the other. If the radius of the narrower can is 12 units, how many units are in the length of the radius of the wider can. I drew a picture to represent the 2 cans. I know that volume of can a=volume of can b. I know the height of can a=3b. I know the radius of can a is 12 units. I know the volume of a cylinder is pi (r)squared (h). I don't know what to do next.
Answer by scott8148(5891) (Show Source):
Question 570716: Jane can paint a 12 by 12 foot wall in 3/4 of an hour. How long will it take her to paint a 15 by 16 feet?
Answer by josmiceli(6786) (Show Source):
You can put this solution on YOUR website! ft2 of area
Jane's rate of painting is  ft2/hr
 ft2/hr
In units:
( ft2 / ( ft2/hr) = hrs
 ft2
It will take her 1 hour and 15 min to
paint the 15x16 ft2 wall
Question 570223: A pool owner is trying to fill his pool. The pump takes 6 hrs. A garden hose takes 10 hours. He wants to fill it up in a hurry. So he turns on the pump AND puts in the garden hose. Unfortunately, he leaves the drain open (which will drain the pool in 8 hours). How long will it take to fill the pool?
Answer by nerdybill(5411)  (Show Source):
You can put this solution on YOUR website! A pool owner is trying to fill his pool. The pump takes 6 hrs. A garden hose takes 10 hours. He wants to fill it up in a hurry. So he turns on the pump AND puts in the garden hose. Unfortunately, he leaves the drain open (which will drain the pool in 8 hours). How long will it take to fill the pool?
Let x = time (hours) it takes to fill pool
then
x(1/6 + 1/10 - 1/8) = 1
multiplying both sides by 6*10*8:
x(80 + 48 - 60) = 6*10*8
x(20 + 48) = 480
x(68) = 480
x = 480/68
x = 7.06 hours
or
x = 7 hours 3 minutes and 32 seconds
Question 569785: A water tank can be filled by any combination of 3 different taps . With the smallest tap the tank can be filled in 20 mins. With the middle tap the tank can be filled in 12 mins. With the largest tap the tank can be filled in 5 minutes .How long does it take to fill the tank with all 3 taps running ?
Explain your reasoning.
Answer by AnlytcPhil(1116)  (Show Source):
Question 569591: It take you 2 min to wash a window, and takes your friend 3 minutes to wash a window. How long does it take the two of you to wash 25 windows if you work together?
Answer by nerdybill(5411) (Show Source):
You can put this solution on YOUR website!It take you 2 min to wash a window, and takes your friend 3 minutes to wash a window. How long does it take the two of you to wash 25 windows if you work together?
.
Let x = time (mins) for both to wash 25 windows
then
x(1/2 + 1/3) = 25
multiplying both sides by 6:
x(3 + 2) = 150
x(5) = 150
x = 150/5
x = 30 minutes
Question 569583: if it takes 3 hours to paint a 100 sq ft wall, how long does it take per sq foot?
Answer by nerdybill(5411) (Show Source):
You can put this solution on YOUR website!if it takes 3 hours to paint a 100 sq ft wall, how long does it take per sq foot?
"3 hours to paint a 100 sq ft" translate to
3 hours per 100 sq ft
or
3/100 hours/sq ft
.03 hours/sq ft
that's .03 hours per sq ft (or, 1.8 minutes)
Question 569234: Carlos can strip a hardwood floor in 3 hours, agnew can strip the same area in 6 hours how long wuld it take the two workers working together?
Answer by stanbon(48558) (Show Source):
You can put this solution on YOUR website!Carlos can strip a hardwood floor in 3 hours, agnew can strip the same area in 6 hours how long wuld it take the two workers working together?
---
Carlos rate: 1/3 job/hr
Agnew rate:: 1/6 job/hr
---
Together rate: 1/x job/hr
-----
Equation:
rate + rate = together rate
1/3 + 1/6 = 1/x
----
2x + x = 6
3x = 6
x = 2 hrs (time to do the job together)
=========================================
cheers,
Stan H.
Question 568937: If a wall was built by 4 men and 2 women in 5 days
how many days it will take to built by 3 men and 1 women?
Found 2 solutions by Theo, bucky:
Answer by Theo(2978)  (Show Source):
You can put this solution on YOUR website!you don't provide any information about how fast each is working, so the assumption is that they all work at the same rate.
if the wall is built by 4 men and 2 women in 5 days, then you calculate their rate of work (how fast they work and their rate of work are used to talk about the same thing) as follows:
rate * time = units of work.
the number of units is 1 (the wall).
the rate that they work is x (we don't know it yet).
the time is 5 days.
we get rate * time = units of work equation becomes:
x * 5 = 1
we divide both sides of the equation by 5 to get:
x = 1/5
the 4 men and 2 women, all working together, have a speed or rate of work that is equivalent to building 1/5 of the wall per day.
if you divide the rate by the number of people, then you get:
1/5 divided by 6 = 1/5 * 1/67 = 1/30.
this means that each person builds 1/30 of the wall per day.
confirm your equation by going back to the original problem.
rate * time = units of work.
the units of work is equal to 1 (the wall).
the rate per person is 1/30 of the wall per day.
the number of people is 6.
the equation becomes:
6 * 1/30 * time = 1
this becomes:
6/30 * time = 1
multiply both sides of this equation by 30/6 to get:
time = 30/6 * 1 which becomes:
time = 5 days.
the equation works with the original situation.
now reduce the number of men and women to 4.
the equation becomes:
4 * 1/30 * time = 1 which becomes 4/30 * time = 1
multiply both sides of this equation by 30/4 to get:
time = 30/4 which becomes:
time = 7.5 days.
all of this assumes that each person is working at the same rate of 1/30 of the wall per day.
there is no distinction between the rate that men work and the rate that women work, nor is there any distinction between the rate that individual people who are different from each other work.
Answer by bucky(2100) (Show Source):
You can put this solution on YOUR website!Lacking further information to the contrary, you can assume that the men and the women have the same working ability. That being the case, the fact that each team is a mixture of men and women has no bearing on this problem. Just count the number of persons on the two teams. Doing this changes the problem to: If a wall was built by 6 persons in 5 days, how many days will it take for 4 persons?
.
That being the case, you can do the problem by determining the number of person-days it takes to build the wall. Do that by multiplying the persons on a team times the number of days it takes. You are told that 6 people can build the wall in 5 days and by multiplying 6 times 5 you can see that it takes 30 person-days to finish the job.
.
The other team consists of 4 persons. In order to put in the 30 person-days needed to build the wall 4 persons will need to work 7.5 days (30 divided by 4).
.
That seems about correct because if 6 people take 5 days to complete the wall, using less people on a team will certainly mean that more than 5 days will be needed to complete the wall. In fact, the ratio of 6 persons to 4 persons tells you how much longer. 6 is to 4 can be reduced to 3 is to 2. So it will take 3/2 times 5 days to complete the job with the smaller team, and 3/2 times 5 days equals 15/2 days which reduces to 7.5 days, the same answer as we previously determined by using person-days.
.
I hope this analytic approach to the problem gives you a better understanding of the procedures that can be used to solve it. Understanding math and using a thought process that applies to the problem is more important than looking for an equation that you can just substitute numbers into to get some sort of an answer, whether it is reasonable or not.
.
Question 567857: A painter can paint a kitchen in 12 hours. An apprentice can paint the same kitchen in 36 hours. If they worked together, how long would it take them to paint the kitchen?
Answer by mananth(10549)  (Show Source):
You can put this solution on YOUR website!Painting the kitchen is 1 job 1 job
Painter 12 hours
he does 1/12 job in 1 hour
Apprentice 36 hours
he does 1/36 of thejob in 1 hour
Together they will do 1/12 + 1/36
Together they will do 1/ 9 of the job in one hour
For 1 job they will take 9 hours
Question 567455: Fred shovels one sidewalk in four minutes, and John shovels one sidewalk in three minutes. How long will it take them to shovel a sidewalk if they work together?
Answer by nyc_function(2645) (Show Source):
Question 567310: A can finish the work in 6 days less than the time taken by B to finish the work.If both of them together can finish it in 4 days, then find the time taken by B alone to finish the workA can finish the work in 6 days less than the time taken by B to finish the work.If both of them together can finish it in 4 days, then find the time taken by B alone to finish the work
Answer by ankor@dixie-net.com(12701) (Show Source):
You can put this solution on YOUR website!A can finish the work in 6 days less than the time taken by B to finish the work.
If both of them together can finish it in 4 days, then find the time taken by B alone to finish the work.
:
Let t = time required by B to do the work
then
(t-6) = time required by A to do it
:
Let the completed job = 1
:
A shared work equation
:
 +  = 1
multiply by t(t-6)
t(t-6)* + t(t-6)* = t(t-6)
cancel the denominators, resulting in
4t + 4(t-6) = t^2 - 6t
4t + 4t - 24 = t^2 - 6t
combine like terms on the right to form a quadratic equation
0 = t^2 - 6t - 8t + 24
t^2 - 14t + 24 = 0
Factors to
(t-12)(t-2) = 0
Two solutions, but only one will make sense
t = 12 hrs for B to do the job alone.
:
:
Check this
 +  =
 +  = 1
Question 567449: 4 painters can paint a house in 3 days, at this rate, how many houses can 6 painters paint in 6 days?
Answer by josmiceli(6786) (Show Source):
You can put this solution on YOUR website!If 4 painters can paint a house in 3 days, then
3 times as many painters can paint a house in
1/3 that time, so 12 painters can paint a house
in 1 day
------------
6 painters will take twice that time,
or 6 painters paint 1 house in 2 days
------------
In 6 days, the 6 painters can paint 3 times as many
houses, so in 6 days 6 painters can paint 3 houses
Question 566734: A pipe is leaking at the rate of 8 fluid ounces per minute. How many gallons is the pipe leaking per hour?
Answer by Alan3354(21605)  (Show Source):
You can put this solution on YOUR website!A pipe is leaking at the rate of 8 fluid ounces per minute. How many gallons is the pipe leaking per hour?
-----------
--> 480 fluid ounces per hour.
How many of those in a gallon?
----
I can see why people don't like metric measurements.
Fluid furlongs, etc.
Question 566530: When Tim and John work together they can mow their entire lawn in 4 hours and 36 minutes. John can mow the entire lawn by himself in 9 hours. How long will it take Tim to mow the entire lawn by himself?
Answer by josmiceli(6786) (Show Source):
You can put this solution on YOUR website!Add their rates of mowing to get rate working together
John's rate: ( 1 lawn ) / ( 9 hrs )
Rate working together: ( 1 lawn ) / ( 4.6 hrs )
Let  = Tim's time in hrs to mow lawn by himself
Tim's rate: ( 1 lawn ) / ( t hrs )
-------------------------
Multiply both sides by 
 hrs
Use calculator to solve
Question 566089: One dran can empty pool in 20 hours, another in 25. If both drains work, how long to empty pool?
Answer by ptaylor(1894)  (Show Source):
You can put this solution on YOUR website!Let x=time required for both drains working together to drain the pool
Then both drains working together drains at the rate of 1/x pool per hour
One drain drains at the rate of 1/20 pool per hour
Another drains at the rate of 1/25 pool per hour
Together they drain at the rate of 1/20 + 1/25 pool per hour, soooo
1/20+1/25=1/x multiply each term by 100x
5x+4x=100
9x=100
x=11.11 hours
CK
In 11.11 hours one drains drains 11.11/20 of the pool
The other drains 11.11/25 of the pool
11.11/20 + 11.11/25 needs to equal 1 (1 pool, that is)
55.55/100 + 44.44/100=99.99/100 Close enough
Hope this helps---ptaylor
Question 565958: A painter paints a wall in x hours, so the fraction of the wall that she paints in 8 hours is
Answer by KMST(600)  (Show Source):
Question 565902: in 2 min a belt moves 300 lbs. a smaller belt moves the same amount the same distance in 6 mins. if both belts r used how long will it take to move the cans?
Answer by stanbon(48558) (Show Source):
You can put this solution on YOUR website!in 2 min a belt moves 300 lbs. a smaller belt moves the same amount the same distance in 6 mins. if both belts r used how long will it take to move the cans?
----
1st belt rate: 1/2 job/min
2nd belt rate: 1/6 job/min
---
Together rate: 1/x job/min
=================================
Equation:
rate + rate = together rate
1/2 + 1/6 = 1/x
3x + x = 6
4x = 6
x = 1.5 min (time for the two belts together to move 300 lbs.)
==============
Cheers,
Stan H.
Question 565478: Left on together, the cold and hot water faucets of a certain buthtub take 7 minutes to fill the tub. If it takes the cold water faucet 17 minutes to fill the tub by itself, how long will it take the hot water faucet to fill the tub on its own? Do not do any rounding.
Answer by ankor@dixie-net.com(12701) (Show Source):
You can put this solution on YOUR website!Left on together, the cold and hot water faucets of a certain bathtub take 7 minutes to fill the tub.
If it takes the cold water faucet 17 minutes to fill the tub by itself, how long will it take the hot water faucet to fill the tub on its own?
:
Let h = the time required by the hot faucet to fill the tub
:
Let the full tub = 1
:
A typical shared work equation
 +  = 1
multiply by 17h, results:
7h + 7(17) = 17h
7h + 119 = 17h
119 = 17h - 7h
119 = 10h
h = 119/10
h = 11.9 min for the hot water to fill it
:
:
Check this:
+  =
.4118 + .5882 = 1
Question 565507: An automatic pitching machine can pitch all its balls in 1 1/4 hours. One attendant working working 3 1/2 hours can retrieve all the balls pitched by one machine. How many attendants working at the same rate should be hired so that the balls from 10 machines are all retrieved in 8 hours.
Answer by ankor@dixie-net.com(12701) (Show Source):
You can put this solution on YOUR website!An automatic pitching machine can pitch all its balls in 1 1/4 hours.
One attendant working working 3 1/2 hours can retrieve all the balls pitched by one machine.
How many attendants working at the same rate should be hired so that the balls from 10 machines are all retrieved in 8 hours.
:
One attendant would take 10*3.5 = 35 hrs to pick up the balls of 10 machines
therefore:
 = 4.375 ~ 5 attendants required pick all the ball from 10 machines in 8 hrs
Question 565498: a water-tank can be filled by any combination of three different taps. with the smallest tap the tank can be filled in 20 minutes.with the middle tap the tank can be filled in 12 minutes.with the largest tap the tank can be filled in 5 minutes.how long does it take with all three taps running?
Answer by scott8148(5891) (Show Source):
Question 565231: Al, Sy, and Ed together can create a web page in 4 hrs. Al can create the webpage in 12 hrs and Sy can do it in 14 hrs. How many hrs would it take Ed to make the webpage alone ?
Answer by solver91311(12126)  (Show Source):
You can put this solution on YOUR website!
This one is a little twist on the typical "Working Together" problem, but the underlying concept is the same.
If A can do a job in x time periods, then A can do  of the job in 1 time period. Likewise, if B can do the same job in y time periods, then B can do  of the job in 1 time period.
So, working together, they can do
of the job in 1 time period.
We don't know what Ed can do by himself, so let's just say that he can do the job in  hours.
Since they get the job done in 4 hours working together, they get  of the job done in 1 hour. So:
All you need to do now is solve for
John
My calculator said it, I believe it, that settles it
Question 564995: Twin brothers, Billy and Bobby, can mow their grandparents lawn together in 89 minutes. Billy could mow the lawn in 30 minutes less time than it would take Bobby. How long would it take Bobby to mow by himself?
Answer by ad_alta(170)  (Show Source):
You can put this solution on YOUR website!Let Billy's rate be 'i' and Bobby's rate be 'o.' Then 1/i=1/o-30. Also, (i+o)*89=1. The first equation tells us that i=-o/(30i+1). So (o-o/(30*o-1))*89=1. That means o=0.005148. So it would take him 1/o or 194.25 minutes.
Question 564582: I need to find out the formula to find out how many minutes it would take to mow an area of grass at the rate of 3 square feet per second? Thanks I have to have it in tonight to put in as computer code. Thanks again.
Answer by Alan3354(21605) (Show Source):
You can put this solution on YOUR website!I need to find out the formula to find out how many minutes it would take to mow an area of grass at the rate of 3 square feet per second? Thanks I have to have it in tonight to put in as computer code.
-------------------
t = area/3 (area in sq ft, time in seconds)
Question 564144: A pond is being drained by a pump. After 3 hours, the pond is half empty. A second pump is put into operation, and together the two pumps finish emptying the pond in half an hour. How long would it take the second pump to drain the pond if it had to do the same job alone.
Found 2 solutions by josmiceli, mananth:
Answer by josmiceli(6786) (Show Source):
You can put this solution on YOUR website!The rate of pumping for the 1st pump
is  ponds/hr
Let the rate of the 2nd pump =  ponds/hr
-----------
Working together,
Multiply both sides by 
 hrs
The 2nd pump can drain 1 pond in 6/11 hrs
This is 32.727 min
32 min and 44 sec
Answer by mananth(10549) (Show Source):
You can put this solution on YOUR website!Pump A -3 hours
so it does 1/3 of the job in 1 hour
Pump A + B = 1/2 hour
so they do 1/(1/2) of the job in 1 hour=2
difference = 2-1/3= 5/6 of the job in 1 hour
so for 1 job Pump B will take 6/5 hours
1 1/5 hours
Question 563876: how many liters of milk would be needed to share 32 children if each child receives a quarter liter of milk?
Answer by josmiceli(6786) (Show Source):
Question 563877: a man brought a box of potatoes which contained 20kg. If he sold them in a half kilogram packets each costing $2.00 how much money did he receive for them?
Answer by josmiceli(6786) (Show Source):
Question 563874: one quarter of a crate can be filled in one minute. How long would it take to fill the crate?
Answer by josmiceli(6786) (Show Source):
Question 563720: If three people working together can clean an office suite in two hours, how long will it take a crew of four people to clean the office?
Found 2 solutions by bucky, solver91311:
Answer by bucky(2100) (Show Source):
You can put this solution on YOUR website!Three people clean the office in 2 hours means that it takes 6 person-hours of work to clean the office (3 persons times 2 hours = 6 person-hours).
.
So 4 persons will need to work 6 person-hours to clean the office.
.
To find the number of hours 4 persons need to work to complete 6 person-hours, divide 4 persons into 6 person-hours and you get the answer of 1.5 hours (4 into 6 = 1.5).
.
Or if you prefer, since a half hour is 30 minutes, 1.5 hours is the same as 1 hour and 30 minutes for the 4 persons to completely clean the office.
.
Hope this helps you to understand the problem.
.
Answer by solver91311(12126) (Show Source):
You can put this solution on YOUR website!
3 people clean 1 office in 2 hours, so
3 people clean 1/2 of an office in 1 hour, so
1 person cleans 1/6 of an office in 1 hour, so
4 people clean 4/6 = 2/3 of an office in 1 hour, so
4 people clean 1 office in 3/2 of an hour, i.e. 1 hour 30 minutes.
John
My calculator said it, I believe it, that settles it
Question 563178: Bill can mow the lawn in 2 hours,and his brother tom can mow it in 3hours.If both brothers mow the lawn together, how many hours will it take them?
Answer by solver91311(12126) (Show Source):
Question 562302: candy and tim share a paper route. it takes candy 70 mins. to deliver all the papers and it takes tim 80 mins. to finish all the papers. how long does it take the two of them when they work together?
Answer by josmiceli(6786) (Show Source):
You can put this solution on YOUR website!Candy's rate is ( all the papers ) / ( 70 min )
Tim's rate is ( all the papers ) / ( 80 min )
Call "all the papers" 1 job
Add their rates to get rate working together
Let = minute to do 1 job working together
Multiply both sides by 
 min
It takes them 37 min and 20 sec working together
Question 562282: at 7:00 am joe starts jogging at 6mi/h . At 7:10 Ken starts off after him. How fast must ken run in order to overtake him at 7:30
Found 2 solutions by mananth, lwsshak3:
Answer by mananth(10549) (Show Source):
You can put this solution on YOUR website!Joe speed = 6 mph
Ken speed = x mph
Joe starts 10 minutes early
so he has run 6*10/60 = 1 mile before ken starts
distance Ken has to run to catch up = 6-1=5 miles
catchup time = 20 minutes ( from 7:10 to 7:30)= 2/3 hours
speed = d/t
speed = 5/(2/3)
speed = 5 *3/2
speed = 15/2 = 7.5 mph
CHECK
catchup time = 2/3
Joe started 1/6 hour early
so he ran for 2/3 +1/6 = 5/6 hours
his speed = 6 mph
5/6 hour *6 = 5 miles
Answer by lwsshak3(2927) (Show Source):
You can put this solution on YOUR website!at 7:00 am joe starts jogging at 6mi/h . At 7:10 Ken starts off after him. How fast must ken run in order to overtake him at 7:30
**
let x=ken's speed (mph)
ken's travel time=7:30-7:10=20 min=1/3 hr
joe's speed=6 mph
joe's travel time=7:30-7:00=30 min=1/2 hr
Both runners covered the same distance
distance=travel time*speed
x*(1/3)=6*(1/2)=3
x=9 mph
ans:
How fast must ken run in order to overtake him at 7:30=9 mph
Question 561857: By himself,Tim can complete his paper route in 120 minutes. With the help of Sue, it takes 90 minutes. How many minutes would it take Sue to do the route by herself?
Answer by ptaylor(1894) (Show Source):
You can put this solution on YOUR website!Let x=time it takes Sue to do the route by herself
Then Sue works at the rate of 1/x of the paper route per min
Tim works at the rate of 1/120 paper route per min
Tim and Sue works at the rate of 1/90 paper route per min
Sooooo our equation to solve is:
1/x + 1/120 =1/90 multiply each term by 360x
360+3x=4x
x=360 min---time it takes Sue to do the route by herself
CK
1/360+1/120=1/90
1/360+3/360=4/360
4/360=4/360
Hope this helps---ptaylor
Question 561809: 4 men take 8 hours to build a wall, how long will it take 7 men to build an identical wall?
Answer by ptaylor(1894) (Show Source):
You can put this solution on YOUR website!OK
If 4 men take 8 hours to build a wall, then the wall require 4*8=32 man hours to build. In other words:
32 men could build the wall in 1 hour
16 men could build the wall in 2 hours
8 men could build the wall in 4 hours
etc
Now 7 men would take 32/7=4.57 hr to build the wall
Another way:
Let x=time it takes 7 men to build the wall
1 man works at the rate of 1/32 of the wall per hour
7 men works at the rate of 7/32 of the wall per hour
soooo
7/32*x=1 (1 wall that is)
x=32/7=same as above
Hope this helps---ptaylor
|
Older solutions: 1..45, 46..90, 91..135, 136..180, 181..225, 226..270, 271..315, 316..360, 361..405, 406..450, 451..495, 496..540, 541..585, 586..630, 631..675, 676..720, 721..765, 766..810, 811..855, 856..900, 901..945, 946..990, 991..1035, 1036..1080, 1081..1125, 1126..1170, 1171..1215, 1216..1260, 1261..1305, 1306..1350, 1351..1395, 1396..1440, 1441..1485, 1486..1530, 1531..1575, 1576..1620, 1621..1665, 1666..1710, 1711..1755, 1756..1800, 1801..1845, 1846..1890, 1891..1935, 1936..1980, 1981..2025, 2026..2070, 2071..2115, 2116..2160, 2161..2205, 2206..2250, 2251..2295, 2296..2340, 2341..2385, 2386..2430, 2431..2475, 2476..2520, 2521..2565, 2566..2610, 2611..2655
|
| |
