tom drives 8km/h faster than amy.

Question

in the same time that Amy drives 360 km, Tom drives 400 km. find the speed of each car. recall that distance=rate*time.

Answer 1

let Amy's speed to x; hence Tom's speed is x + 8

 

xt = 360 (Amy)   therefore t = 360/x

 

(x + 8)t = 400 (Tom)    therefore t = 400/(x + 8)

 

Since the times are the same, t = 360/x = 400/(x + 8)

 

cross multiplying ; 360(x + 8) = 400x

 

2880 = 40x ; x = 2880/40 = 72 kph

 

Mary's speed is 72 kph and Tom's speed is 72 + 8 = 80 kph