A cyclist rides from town A to town B, which is 60 km away, at a speed of 15 km/h. After reaching town B, the cyclist immediately turns back and rides towards town A at a speed of 10 km/h. What is the cyclist's average speed for the entire journey?
Show answer & explanation
Correct answer: B
Explanation
Distance from A to B = 60 km
Distance from B to A = 60 km
Total distance = 120 km
Time taken for the outward journey = 60 / 15 = 4 hours
Time taken for the return journey = 60 / 10 = 6 hours
Total time = 4 + 6 = 10 hours
Average speed = Total distance / Total time= 120 / 10= 12 km/h