walk @ 5mph, jog twice as far @ 8mph; total time 2hr 15min

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kilrif

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Sep 6, 2008
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I need help solving the following..

Sue is in a walkathon. Sue walked a certain distance at 5 mph and then jogged twice that distance at 8mph. Her total time is 2hr and 15 min. How many miles long was the walkathon?

Can you tell me how to set up to solve???

Kind thanks! :D
 
Re: Help! Distance/Time/Rate Problem

kilrif said:
I need help solving the following..

Sue is in a walkathon. Sue walked a certain distance at 5 mph and then jogged twice that distance at 8mph. Her total time is 2hr and 15 min. How many miles long was the walkathon?

Can you tell me how to set up to solve???

Kind thanks! :D
Click to expand...

Please share with us your work/thoughts so that we know where to begin to help.
 
Re: Help! Distance/Time/Rate Problem

Ok..this what I did...

D = R(T)

D=5T
2D = 8(2.25-T)
and then attempted to add vertically to finally get

3D = 18-3T

But then got so confused as I have too many variables :?

Arg :(
 
Re: Help! Distance/Time/Rate Problem

What you are doing is good. Just continue.

\(\displaystyle 2d=8(2.25-t)\)

\(\displaystyle d=5t\)

Then we get \(\displaystyle 10t=2(2.25-t)\)

Solve for t and use it in each equation to find the total distance.

We can also do this:

We know that d=rt, therefore, t=d/r.

They are asking for distance so we set it up as a time equation and solve for d. See what I mean?.

The first time is d/5

The second time has twice the distance d so it is 2d/8

The total is 9/4=2.25 hours

So, we have \(\displaystyle \frac{d}{5}+\frac{2d}{8}=\frac{9}{4}\)

Solve for d.
 
Re: Help! Distance/Time/Rate Problem

Remember that the question asked you to find total distance of the walkathon.
 
Re: Help! Distance/Time/Rate Problem

You guys are great...Thank you, galactus, for showing me the alternate method which I understood vs the way I attempted. :D Total time as khan focused on is the 5 miles + 10 miles for a total 15 mile walkathon!
Yippee....now back to my Saturday!
 
Re: Help! Distance/Time/Rate Problem

You got it. Good. :D
 
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