Question

john and peter started jogging from the same place at the same time, but in opposite directions along a straight road. After jogging for 3 hours, they were 27 km apart. If john's average speed was 6 km/h, what is peters speed?

Answer 1

Answer: 3km/h

Explanation:

Johns average speed was 6km/h, so in 3 hours he traveled 18 km. 27-18=9, so Peter ran 9 km in 3 hours. 9/3 = 3, so his average speed was 3km/h

Answer 2

3 km/h

Explanation:

Distance = speed x time

The distance apart equals to the sum of the distance that John jogged, and the distance that Peter jogged since they go opposite directions.

Hence,

let v be peter's speed

27 = 6x3 + vx3

27 = 18 + 3v

27-18 = 3v

9 = 3v

v = 9/3

v = 3 km/h