jlgdr wrote:

agnok wrote:

At what rate must Eden travel to overtake Rex, who is traveling at a rate 20 mph slower than Eden. If Eden starts 2 hours after Rex and wants to overtake him in 4 hours...

Please show steps to solve

Answer Eden should travel at 60 mph

Check this out we want to know the following

(E-R)(4) = 2R

This means that 'E-R' is the relative speed at which E will travel faster than Rex to overtake him.

4 hours is the required time

The distance is 2R because that's what Rex traveled in the two hour headstart

Therefore solving we get 2E = 3R

Now we are also told that R = E-20

So we can replace and one will get E = 60

Hope it helps!

Cheers!

J

Here's another way to solve this:

E is X, Therefore R (X-20). The distance traveled by Rex in 2 hrs is 2x - 40.

We need Eden to overtake him in 4 hrs.

Thus, 4(x-(x-20)) = 2x - 40. Solving we get that x =60.

Hope this helps

Cheers

J