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josmiceli answered: 9683 problems
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Answer 454105 by josmiceli(9685) on 2013-05-07 14:52:34 (Show Source):
You can put this solution on YOUR website!The key is to see that ( miles driven ) / ( miles / gallon ) = gallons
I can say:
Let  = mpg on the highway
Let  = mpg in town
(1) 
(2) 
-----------------------------
(1) 
(2) 
------------------------------
Multiply both sides of (2) by 
and subtract (1) from (2)
(2) 
(1)

and
(2) 
(2) 
(2) 
(2) 
(2) 
-----------------
His highway m.p.g. was about 22
and his local m.p.g. was about 11
-----------------
check:
(1) 
(1) 
(1) 
close enough
|
Reduction-of-unit-multipliers/746011: a water hose can fill a 1 quart bottle with water in 2.2 seconds; I need to buy a pond pump but its flow rates are given in gallons per hour. what size pump should I purchase to the nearest 100 GPH? 1 solutions
Answer 454103 by josmiceli(9685) on 2013-05-07 14:32:10 (Show Source):
You can put this solution on YOUR website!You want an answer in ( gallons / hr ), so
in terms of just units:
( quarts / sec ) x ( gallons / quart ) x ( sec / min ) x ( min / hr ) = ( gallons / hr )
-----------------------
This is easier to see if you pull out all the like units:
( quarts / quarts ) x ( sec/ sec ) x ( min / min ) x ( gallons / hr ) = ( gallons / hr )
-------------
Using your numbers:

To the nearest 100 GPH, you need a 400 GPH pump
|
Rate-of-work-word-problems/745788: Peter and Paul can do a certaion job in 3 hours. On a given day, they worked together for 1 hour then Paul left and Peter finishes the rest of the work in 8 more hours. How long will it take Peter to do the job alone? 1 solutions
Answer 454019 by josmiceli(9685) on 2013-05-06 23:25:05 (Show Source):
You can put this solution on YOUR website!If they can do the whole job in 3 hrs working
together, then in 1 hour, they can do
of the job
That means there is 2/3 of the job left to do
-----------------
Then, ( Peter's rate of working ) x ( 8 hrs ) = 2/3
Let  = Peter's rate of working

Peter would take 12 hrs to do the job alone
check:
----------
Let  = Paul's rate of working

In  hr,

So,  of the job is left
Peter does

OK
|
Rate-of-work-word-problems/745794: father and a his son can dig a well if the father works 6 hours and his son works 12 hours or they can do its if the father works 9 hours and the son works 8 hours. How long will it take for the son to dig the well alone? 1 solutions
Answer 454007 by josmiceli(9685) on 2013-05-06 22:10:56 (Show Source):
You can put this solution on YOUR website!You can add their rates of digging to get their rate
working together
Let  = father's rate of digging
Let  = Son's rate of digging
--------------------------------
In general, I can say that:
( time spent digging ) x ( rate of digging ) = fraction of job done
---------------
given:
(1) 
(2) 
( note that  means entire job done )
----------------
Multiply both sides of (1) by  and
both sides of (2) by 
Then subtract (2) from (1)
----------------------
(1) 
(2)

-----------------
(1) 
(1) 
(1) 
(1) 
(1) 
(1) 
(1) 
(1) 
-----------------
The son would take 20 hrs working alone
check:
(2) 
(2) 
(2) 
(2) 
(2) 
OK
|
Travel_Word_Problems/745513: THE HEIGHT OF THE ROCKET AFTER t SECONDS WHEN FIRED STRAIGHT UP WITH AN INITIAL SPEED OF 150FT PER SECOND FROM AN INITIAL HEIGHT OF 2 CAN BE MODELED BY THE FUNCTION: s(t)=-16t^2+150t+2
WHEN WILL THE ROCKET BE 300ft?
WHAT IS THE MEANING OF THE Y INTERCEPT
WHEN WILL IT REACH THE GROUND?
I AM UNSURE OF HOW TO START THE PROBLEM. DO I USE THE QUADRATIC FORMULA?
1 solutions
Answer 453866 by josmiceli(9685) on 2013-05-06 11:01:46 (Show Source):
|
Money_Word_Problems/745328: In 1980 the average price of a home in Brainerd County was $95,000. By 1987 the average price of a home was $123,000. Which of the following is a linear model for the price of a home, P in brainerd County in terms of a year, t? let t=0 correspond to 1980.
Answers:
A) P=123,000-4000t B) P=4000t+95,000
C) P= 123,000- 28,000t D) P= 28,000t + 95,000 1 solutions
Answer 453803 by josmiceli(9685) on 2013-05-05 20:11:51 (Show Source):
|
Travel_Word_Problems/745124: When Mr. Gomez drives his car to work, the trip takes 30 minutes. When he rides the bus, it takes 45 minutes. If his average driving speed is 12 mph faster than the average speed of the bus, find the distance he travels to work.
1 solutions
Answer 453738 by josmiceli(9685) on 2013-05-05 13:07:44 (Show Source):
You can put this solution on YOUR website!Let  = the distance to work
Let  = the speed of the bus
Convert minutes to hours
By car:
(1) 
By bus:
(2) 
------------------
Substitute (2) into (1)
(1) 
Multiply both sides by 
(1) 
(1) 
(1) 
Substitute this result into (2)
(2) 
(2) 
(2) 
The distance to work is 18 miles
|
Functions/745110: The height s, in feet, of a rock thrown upward at an initial speed of 64 ft/sec from a cliff 50 ft above an ocean beach is given by the function s(t)=-16t^2+64t+50, where t is the time in seconds. Find the maximum height above the beach that the rock will attain. 1 solutions
Answer 453737 by josmiceli(9685) on 2013-05-05 12:56:57 (Show Source):
You can put this solution on YOUR website!The maximum height of this parabolic curve is
 when  and
the equation has the form:

In your equation,
 , so
 sec
--------------
Now find  which is the maximum height
 ft
The maximum height is 114 ft
Here's the plot:
|
Travel_Word_Problems/745117: Megan is going on a long distance road trip. She drives for 14 miles before being able to travel at a constant speed using cruise control. The equation y = 70x + 14 can be used to find her total distance traveled. If y is the total number of miles driven, and x is the number of hours driven after reaching 14 miles, which statement best describes the rate of change in the distance traveled? 1 solutions
Answer 453736 by josmiceli(9685) on 2013-05-05 12:45:08 (Show Source):
You can put this solution on YOUR website!The rate of change of the distance traveled is
the slope of the equation, which is:
( change in y ) / ( change in x ) = 70 mi/hr
|
Mixture_Word_Problems/744992: Wilma went to the local market and bought 3 lemons and 5 oranges for $2.40.The same day and for the same price ,Fran bought 4 lemons and 7 oranges for $3.31.What was the prices per lemon and the price per orange?
Answer is $o.25 per lemon and $.33 per orange 1 solutions
Answer 453642 by josmiceli(9685) on 2013-05-04 21:46:45 (Show Source):
You can put this solution on YOUR website!Let  = price of a lemon
Let  = price of an orange
given:
(1)  ( in cents )
(2)  ( in cents )
--------------------
Multiply both sides of (1) by 
and both sides of (2) by 
Then subtract (1) from (2)
(2) 
(1)

and
(1)
(1) 
(1) 
(1) 
25 cents /lemon and
33 cents/orange
|
Miscellaneous_Word_Problems/744942: A herd of 575 deer is introduced onto a small. island. At first the herd increases rapidly, but eventually food resources dwindle and the population declines. suppose that the number of deer after t years is given by the following formula
N(t)= -t^4 + 2t^2 + 575
please show a step by step on how you got your answer 1 solutions
Answer 453639 by josmiceli(9685) on 2013-05-04 21:36:21 (Show Source):
|
Travel_Word_Problems/744989: 1) At 6 a.m., a passenger train and a freight train leave stations that
are 360 miles apart and travel toward each other. The passenger train averages twice the speed of the freight train. At 10 a.m., the trains pass each other.
Write and solve an equation to find the average speed of each train 1 solutions
Answer 453638 by josmiceli(9685) on 2013-05-04 21:27:44 (Show Source):
You can put this solution on YOUR website!Think of one train as standing still and the
other approaching at the sum of their speeds
( it doesn't matter which train is moving )
--------------------------------------
Let  = the speed of the slower train
 = the speed of the faster train
The time the moving train is traveling is
10 AM minus 6 AM =  hrs
----------------------------

The average speed of the freight train is 30 mi/hr
The average speed of the passenger train is 60 mi/hr
---------------
check:
freight train:

---------------
passenger train:

--------------
 mi
OK
|
Mixture_Word_Problems/744940: three solutions contain a certain acid. the first contains 15% acid, the second 35%, and the third 40%. A chemist wishes to use all three solutions to obtain a 75-liter mixture containing 34% acid. If the chemist wants to use twice as much of the 35% solution as of the 40% solution, how many liters, to the nearest 10th, of each solution should be used? 1 solutions
Answer 453617 by josmiceli(9685) on 2013-05-04 16:43:03 (Show Source):
You can put this solution on YOUR website!Let  = liters of 40% solution needed
 = liters of 35% solution needed
Let  = liters of 15% solution needed
---------------
 = liters of acid in 40% solution
 = liters of acid in 35% solution
 = liters of acid in 15% solution
----------------
(1) 
(2) 
----------------
(1) 
and
(2) 
(2) 
(2) 
----------------
Multiply both sides of (1) by 
and subtract (1) from (2)
(2) 
(1)

and, since
(1) 
(1)
(1) 
(1) 
21.9 liters of 40% solution are needed
43.8 liters of 35% solution needed
9.2 liters of 15% solution are needed
--------------
check:
(2) 
(2) 
(2) 
(2) 
OK
|
logarithm/744927: If log(base 3)2 = x simplify each logarithm
a) log(base 3)8
b) log(base 3)24
c) log(base 3)√2
d) log(base 3)6√2
Can you please help me out? Thanks so much in advance:)
Can you also show all the steps because it would help me understand :) 1 solutions
Answer 453615 by josmiceli(9685) on 2013-05-04 16:12:49 (Show Source):
|
Travel_Word_Problems/744932: two airplanes start at the same time and fly toward each other from points 200 km apart at rates of 350 km/h and 400km/h when will they meet 1 solutions
Answer 453614 by josmiceli(9685) on 2013-05-04 15:49:57 (Show Source):
You can put this solution on YOUR website!Think of one plane as standing still and the
other approaching at the sum of their speeds.
Equation for the moving plane:
 hrs
 min
They will meet in 16 min
|
logarithm/744755: Show that log(base 1/c)x = log(base c)1/x
Can you please help me out with this question? Thanks so much in advance:)
Can you show all the steps because it will help me understand more thanks 1 solutions
Answer 453525 by josmiceli(9685) on 2013-05-03 19:53:51 (Show Source):
|
Quadratic_Equations/744337: Karens Backyard has a width of 25 meters and a length of 35 meters. SHe wants to put a rectangular flower garden in the middle of the backyard leaving a strip of grass of uniform width around all sides of the flower garden. If she wants to have 324 square meters of grass what will be the width and length of the garden 1 solutions
Answer 453270 by josmiceli(9685) on 2013-05-02 15:59:21 (Show Source):
You can put this solution on YOUR website!Let  = the uniform width of the grass border
The dimensions of the rectangular flower garden
can be expressed as:
width =  m
length =  m
----------------------
She wants to have  square meters of grass
Her whole backyard has an area of  m2
--------------
The area of her garden is 
Now I can say:
 ( by inspection )
The width of the border can't be  , since
that is wider than her backyard, so
width =  m
length =  m
--------------------------
check answers:

OK
|
Miscellaneous_Word_Problems/744333: A train ticket has an area of 192 square centimeter and a perimeter of 56 centimeters. What are the dimensions of the tickets. 1 solutions
Answer 453266 by josmiceli(9685) on 2013-05-02 15:39:33 (Show Source):
You can put this solution on YOUR website! = length in cm
 = width in cm
 = area in cm2
 = perimeter in cm
----------------
(1) 
(2) 
---------------
given:
(1) 
and
(2) 
(2) 
(2) 
By substitution:
(1) 
(1)

and, also

-----------
If I pick the larger answer, then
(2) 
(2) 
(2) 
---------------
These are the answers, because if I picked  ,
then I would get  for the width
----------
The length is 16 cm
The width is 12 cm
|
Rate-of-work-word-problems/744074: Billy's pool has a hole and is losing water at a rate of 4/9 gallon per minute. How many hours will it take for Bill to lose 100 gallons?
1 solutions
Answer 453185 by josmiceli(9685) on 2013-05-01 21:48:50 (Show Source):
You can put this solution on YOUR website!In terms of units:
( gallons ) / ( gallons / min ) = min

This answer is in minutes. To get hours:
( minutes ) x ( hours / minute ) = hours

and 
It will take Bill 3 hrs and 45 min
|
Equations/744041: can I get the expression and define the variables for this word problem:
The cost of gas is 3.35 per gallon. If you travel 40 miles a day and gas mileage is 25 miles per gallon. How much gas money will be spent in a 5 day work week? 1 solutions
Answer 453153 by josmiceli(9685) on 2013-05-01 18:42:18 (Show Source):
You can put this solution on YOUR website!In terms of units:
( dollars / gallon ) x ( ( miles / day ) / ( miles / gallon ) ) x ( days )
After doing the division, you get:
( dollars / gallon ) x ( miles / day ) x ( gallons / mile ) x ( days )
Now I'll do a slight reordering:
( dollars / gallon ) x ( gallons / mile ) x ( miles / day ) x ( days )
Doing the cancellations, I get:
( dollars / mile ) x ( miles ) = dollars
Which is what you're after
Now, plugging in the numbers:

For a 5 day work week, $26.80 is spent
|
test/744036: 10zē+3z-3=0 I need to know what is the discriminant? Is it positive or negative? What kind of solution would you get if the discriminant were negative?
Thank You! 1 solutions
Answer 453150 by josmiceli(9685) on 2013-05-01 18:26:57 (Show Source):
You can put this solution on YOUR website!When the equation has the form
 , then the roots are found
using the quadratic formula:

The discriminant is:

If the discriminant is positive, both roots are real
If the discriminant is negative, both roots are imaginary
If the discriminant is zero, there is 1 real root
------------------
Your equation is:

and the discriminant is:

This result is positive, so there are 2 real roots
Here is the plot:
|
Rate-of-work-word-problems/744030: one printing machine works twice as fast as another. When both machines are used, they can print a magazine in 3 hrs. How many hours would each machine require to do the job alone?
1 solutions
Answer 453146 by josmiceli(9685) on 2013-05-01 18:11:12 (Show Source):
You can put this solution on YOUR website!Add their rates of printing
Let  = the slower machine's rate of printing
 = the faster machine's rate of printing
When both machines are used, their rate of printing is
( 1 magazine ) / ( 3 hrs )
---------------------

The fast machine can print a magazine in 4.5 hrs
The slow machine can print a magazine in 9 hrs
|
Rational-functions/743970: It take one pipe 3 hours to fill the pool and a second pipe 4 hours to drain a pool. The pool is empty and the first pipe begins to fill it. The second pipe is accidentally left open, so the water is also draining out of the pool. Under these conditions how long will it take to fill the pool? 1 solutions
Answer 453120 by josmiceli(9685) on 2013-05-01 16:39:24 (Show Source):
You can put this solution on YOUR website!Add the rate of filling and subtract the rate
of draining.
Let  = time in hrs to fill pool with both pipes open
( 1 pool filled ) / ( 3 hrs ) - ( 1 pool emptied ) / ( 4 hrs ) = ( 1 pool filled ) / ( t hrs )

Multiply both sides by

It will take 12 hrs to fill the pool
|
Travel_Word_Problems/743918: Flying with the wind, a plane traveled 510 miles in 3 hours. Flying against the wind, the plane traveled the same distance in 5 hours. Find the rate of the plane in calm air and the rate of the wind. 1 solutions
Answer 453099 by josmiceli(9685) on 2013-05-01 15:10:11 (Show Source):
You can put this solution on YOUR website!Let  = the speed of the plane in still air in mi/hr
Let  = the speed of the wind in mi/hr
 = plane's speed flying with the wind in mi/hr
 = plane's speed flying against the wind in mi/hr
--------------------
Flying with the wind:
(1) 
Flying against the wind:
(2) 
----------------------
(1) 
and
(2) 
---------------------
(1) 
(2) 
Add the equations

and
(1) 
(1) 
The rate of the plane in calm air is 136 mi/hr
The rate of the wind is 34 mi/hr
check:
(2) 
(2) 
OK
|
Travel_Word_Problems/743802: The speed of a bayou near Lafayette, Louisiana is 4 miles per hour. A paddle boat travels 48 miles upstream in the same amount of time it takes to travel 72 miles downstream. Find the speed of the boat in still water. 1 solutions
Answer 453074 by josmiceli(9685) on 2013-05-01 09:52:57 (Show Source):
You can put this solution on YOUR website!Let  = the speed of the boat in still water
 = speed going downstream
 = speed going upstream
Let  = time for both trips
-------------
Going upstream:
(1) 
Going downstream:
(2) 
---------------------
This is 2 equations and 2 unknowns, so you
can solve for  and
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