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Rate-of-work-word-problems/417545: A moving sidewalk at an airport is glides at a rate of 1.8 feet per second. Walking on the moving sidewalk, you travel 105 feet forward in the same time it takes to travel 50 feet in the opposite direction. Assuming that you walk at the same pace, find your walking speed if you were on a flat, non-moving sidewalk. Round to the nearest tenth.
1 solutions
Answer 292325 by josmiceli(9668)   on 2011-03-04 16:31:29 (Show Source):
You can put this solution on YOUR website!Let  = walking speed
given:
(1) 
and
(2) 
------------------
From (2)
By substitution:
(1) 
(1) 
(1) 
(1) 
and
(2) 
(2) 
(2) 
(2)  ft/sec
check:
(2)
(2) 
(2) 
(2) 
OK
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expressions/417563: dont understand this problem and solution teacher put on board could you help me understand? I dont get it.
4y=2x-10
2y=2(5+2y)-10
4y=10+4y-10
4y-4y=10-10
0=0
=
1 solutions
Answer 292318 by josmiceli(9668) on 2011-03-04 16:10:19 (Show Source):
You can put this solution on YOUR website!4y=2x-10
4y=2(5+2y)-10
4y=10+4y-10
4y-4y=10-10
0=0
------------
I get what what the teacher has in mind. At the beginning, there
must have been 2 equations:
(1) 
and
(2) 
What the teacher was trying to show is that these equations are
exactly the same. (S)he did this by trying to "solve" for x and y
in the normal way, by substitution. If the equations were different,
this would have resulted in a solution (x,y).
-------------
To show the equations are the same, subtract  from both sides
of (2). Then you have:
(2) 
Now multiply both sides by 
(2)
So, if both equations are the same, there is no solution. Also if the
equations are different, but have the same slope, tyhere can be no
solution, since they would be parallel lines that never meet.
An example would be:
(1) 
(2) 
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Money_Word_Problems/417466: A woman invested 4 times as much at 5% as she did at 6%. The total amount of interest she earns in 1 year from both accounts is $520. How much did she invest at each rate?
1 solutions
Answer 292252 by josmiceli(9668) on 2011-03-04 12:14:38 (Show Source):
You can put this solution on YOUR website!Let  = amount invested @ 6%
given:
 = amount invested @ 5%
-------------------------
She invested $2019.23 @ 6%
She invested $8076.92 @ 5%
check answer:
 (close enough)
|
Mixture_Word_Problems/417064: Doreen is a chemist. she needs to prepare 24 ounces of a 7% solution. Find the amount of 12% solution and the amount of a 6% solution she should mix to get this solution?
Amount of 12%:
Amount of 6%:
1 solutions
Answer 292069 by josmiceli(9668) on 2011-03-03 18:00:10 (Show Source):
You can put this solution on YOUR website!Let  = ounces of 6% solution needed
Let  = ounces of 12% solution needed
--------
given:
(1) 
(2) 
---------
(2) 
Multiply both sides of (1) by 
and subtract from (2)
(2)
(1) 
and
She needs 20 ounces of 6% solution and
4 ounces of 12% solution
|
Graphs/417066: solve and graph
-8 < 3x+1 and 3x+1 < 16
the arrows have lines under them
the solution is {x|_ < x < __}
the arrows have lines under them
1 solutions
Answer 292065 by josmiceli(9668) on 2011-03-03 17:48:19 (Show Source):
You can put this solution on YOUR website!
Subtract 
Divide by 
The graph is 2 vertical lines, one at 
and the other at  . The
solution is the space between the lines,
including the lines.
|
percentage/417067: Identify as an increase or decrease. Then find the percent of increase or decrease. If necessary, round to the nearest percent.
Original: 180
New: 190
___% increasing or decreasing?
1 solutions
Answer 292060 by josmiceli(9668) on 2011-03-03 17:42:04 (Show Source):
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Volume/416977: a fish tank is 25 inches tall and has a base that is 15 by 19 inches you want to fill the tank to a depth of 23 inches how much water will it take
i want to know how to do it
1 solutions
Answer 292026 by josmiceli(9668) on 2011-03-03 15:45:33 (Show Source):
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Travel_Word_Problems/416966: A car travels for 40miles with an average velocirty of 30mph and then for 30 minutes at an average velocity of 50mph. What is the average velocity of the car for the entire trip?
1 solutions
Answer 292023 by josmiceli(9668) on 2011-03-03 15:42:28 (Show Source):
You can put this solution on YOUR website!Average velocity is always (total distance)/(total time)
 mi / (mi/hr) =  hrs (time for 1st trip)
 hrs (time for 2nd trip)
 mi/hr * hrs = mi (2nd trip)
 = average velocity
 mi/hr
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Word_Problems_With_Coins/416972: coin collector had 6 coins for sale
one he price @15,16,18,19,20,31 he sold all but one of the coins
to 2 people one payinng 2xs as much as the other one
which coin did he keep
1 solutions
Answer 292019 by josmiceli(9668) on 2011-03-03 15:31:10 (Show Source):
You can put this solution on YOUR website!I just tried every single number that could be the one left out
First I let = the amount one person paid and  =
amount other person paid.  , so the sum of
what they bought must be divisible by
The only way I could arrive at this is if the coin costing 20
is left out. Then  , so if
1 person bought 33 worth of coins
The other bought 66 worth
and
So, he kept the coin costing 20
|
Equations/416573: my son has brought an alegebra worksheet home and he needs help with working these types of problems.
f(x)=4x-2y, find f(7)
1 solutions
Answer 291843 by josmiceli(9668) on 2011-03-02 19:10:19 (Show Source):
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Travel_Word_Problems/416526: two ships leave port at the same time. Ship #1 travels north and ship #2 travels east. After 1 hour the ships are 25 miles apart. Ship #1 travels 5 miles faster than ship #2. How fast are the ships traveling.
I used the formula A^2 + b^2 = C^2 butr the answer is not right. Please help
X^2 + (X+5)^2 = 25 ^2
2x^2 + 10 X = 600
2x^2 = 60
X^2 = 30
x= 5.5
1 solutions
Answer 291825 by josmiceli(9668) on 2011-03-02 18:22:49 (Show Source):
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Mixture_Word_Problems/416360: combine an alloy that costs $4.30 and ounce with an alloy that cost $1.80 an ounce. Hou many ounces of each were used to make a mixture of 200 ounces costing $2.50 per ounce?
1 solutions
Answer 291714 by josmiceli(9668) on 2011-03-02 14:24:25 (Show Source):
You can put this solution on YOUR website!Let = ounces of $4.30/oz alloy needed
Let = ounces of $1.80/ oz alloy needed
In words:
(cost of 1st alloy + cost of 2nd alloy) / (total ounces of both) = cost/ounce
(1) 
(2) 
-----------------
(1)
(1) 
(1) 
-----------------
Multiply both sides of (2) by  and
subtract from (1)
(1)
(2) 
and,
56 ounces of $4.30/oz alloy are needed
144 ounces of $1.80/ oz alloy are needed
check answer:
(1)
(1) 
(1)
OK
|
Quadratic_Equations/416358: help me with this question. the directions are slove each equation by graphing. If integral roots cannot be found, estimate the roots by stating the consecutive integers between which the roots lie. The question is X^2 + 7x + 9.
1 solutions
Answer 291707 by josmiceli(9668) on 2011-03-02 14:06:34 (Show Source):
You can put this solution on YOUR website!I would use the fact that the minimum on the graph is at 
when the form is  , so min = 
The roots will be on either side of this. You can try
(1)  and .
Then try
(2)  and  ,
next
(3)  and 
-----------------------
Here's the graph:
You can see that  will change sign when you go
from choice (2) to choice (3) above
|
Quadratic_Equations/416352: A car travels 300 km at a certain speed. If the speed had been increased by 10 km/h, the trip could have been made in 1 hour or less time. Find the actual speed.
s = d/t
s = 300/60 = 50 what about the 10 increase
1 solutions
Answer 291704 by josmiceli(9668) on 2011-03-02 13:51:51 (Show Source):
You can put this solution on YOUR website!Let  = speed without the  km/hr increase
(1) 
And with the increase in speed:
(2) 
-----------------
This is 2 equations and 2 unknowns, so it's solvable
(2) 
(2) 
The actual speed is 290 km/hr
|
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