Starting from a common point, John and Roger drove 294 km towards the same destination. John drove his van 7 kph slower than Roger. It took John an hour longer than Roger. What was John's rate?

Answer 1

R=7+J

Rt =J(t+1) = 294

(7+J)t = J(t+1)

7t + Jt = Jt + J

7t = J

7t(t+1)=294

t(t+1) = 42

t^2 + t -42=0

(t+7)(t-6) =0

t=6 hours for Roger

J= 7t = 7(6) = 42 kph for John

R=49 kph for Roger

John took 7 hours at 42 kph. 7x42 = 294 km

Roger took 6 hours at 49 kph. 6x49= 294 km