Distance Problem

Question

Two people start walking across a 60ft bridge at the same time.  The second person's speed was 12ft per min faster than the first persons speed.  If the second person finished walking across 2.5 mines before the first what is the first person's speed in ft per minute?

Answer 1

OK, here we go

 

First, remember that they both have to walk 60 feet.  Since you do not mention acceleration, I assume that they move at constant speed.

 

Call the speed of the first person V_1 and the second person V_2.  They tell us that V_2 is 12 feet/min faster than V_1 so we have

 

V_2 = V_1 + 12

 

Call the time it takes the first person to cover the bridge t.  So, the time for the second person is (t-2.5) since the second person started 2.5 minutes sooner.

 

Now, the distance for person 1 is V_1*t and for person 2 it is V_2*(t-2,5) = (V_1+12)*(t-2.5).  Since they both travel the same distance, we can set these two equal so that V_1*t = (V_1+12)*(t-2.5).  Solve for V_1.