another rate word problem

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wrightka

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Jul 16, 2009
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I have to take a General Knowledge test soon, but I am having trouble understanding how to set up equations for word problems especially rate word problems.
The study guide is not helping much and It only gave me 3 rate problems to practice with. Here is the second one:
A camper leaves the campsite walking due east at a rate of 3.5mph. Another camper leaves the same campsite at the same time traveling due West. In two hours the campers are 15 miles apart. What is the walking rate of the second camper?
Again I have no clue!
X= walking rate of second camper
3.5mph=walking rate of first camper.
In two hours, they were 15 miles apart
All I can come up with is rate x time = distance
(x+3.5mph) = 15miles/2hours
= 2x +7 =15
2x=15-7
2x=8
x=4 but not right, the answer is supposed to be 2.5mph
 
wrightka said:
I have to take a General Knowledge test soon, but I am having trouble understanding how to set up equations for word problems especially rate word problems.
The study guide is not helping much and It only gave me 3 rate problems to practice with. Here is the second one:
A camper leaves the campsite walking due east at a rate of 3.5mph. Another camper leaves the same campsite at the same time traveling due West. In two hours the campers are 15 miles apart. What is the walking rate of the second camper?
Again I have no clue!
X= walking rate of second camper
3.5mph=walking rate of first camper.
In two hours, they were 15 miles apart
All I can come up with is rate x time = distance
(x+3.5mph) = 15miles/2hours
= 2x +7 =15
2x=15-7
2x=8
x=4 but not right, the answer is supposed to be 2.5mph
Click to expand...

Use the hints given in your other post:

viewtopic.php?f=9&t=35248

First, you need to find the distances each camper walks (the distance that the second camper walks will be a function of 'x') in two hours.

Then add those up - to equal to 15

Now solve for 'x'
 
Have you copied something wrong? It appears to me that your answer of 4 mph is correct.
 
I agree with Loren. 4 mph is correct.

\(\displaystyle 3.5(2)+2r=15\)

\(\displaystyle r=4\)
 
Hello, wrightka!

With a little Thought, we don't need Algebra . . .

A camper leaves the campsite walking due east at a rate of 3.5 mph.
Another camper leaves the same campsite at the same time traveling due West.
In two hours the campers are 15 miles apart.
What is the walking rate of the second camper?
Click to expand...
. . .\(\displaystyle B \qquad\qquad\quad\;\; C \qquad\qquad A\)
. . . \(\displaystyle * \leftarrow - - - - * - -\, - \rightarrow *\)
. \(\displaystyle 8 \qquad\qquad 7\)

Camper A walked east for 2 hours at 3.5 mph.
. . He is 7 miles east of the campsite.

Then Camper B must be 8 miles west of the campsite.

Since he too walked for two hours, how fast was he walking?

 
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