Question

Cars A and B are travelling 30 and 40 miles per hour, respectively. If car B starts out 5 miles behind car A, how many hours will it take for car B to overtake car A?

Answer 1

Solve the following equation for t:
30 t + 5 = 40 t
t=1/2 hour

Answer 2

Now for this problem the distance from the origin be x at which b overtake a

then


x x - 5
-- = --------
40 30


which will give x = 20

now calculate time which will be 20/40 = 1/2hr