Question 1179934

Justin can run 10 km in the same amount of time that Leo can run 12 km. if Leo can run 1 kph faster than Justin, how fast can Leo run?
let Justin's speed be x km/h
Leo's speed = x+1 km/h

Justin's time = 10/x

Leo's time = 12/(x+1)

Both times are equal
10/x = 12/(x+1)

10(x+1) =12x

10x +10 =12x
2x=10
x= 5  Justin's speed

Leo's speed = 6 km/h