Question

a biker must circle a 12 mile track twice. His average speed must be 60mph. On his first lap he averaged 50 mph. How fast must he travel on his second lap to qualify?

Answer 1

75 mph

Explanation:

A biker must circle a 12-mile track twice. His average speed must be 60 mph.

So, the average time required to cover the distance is
`(2 * 12)/(60) = 0.4` hours.

Now, on his first lap, he averaged 50 mph.

So, he covered this 12 miles track in
`(12)/(50) = 0.24` hours.

Hence, he has to cover the next 12 miles track in (0.4 - 0.24) = 0.16 hours.

Therefore, his average speed in the second round must be
`(12)/(0.16) = 75` mph to qualify. (Answer)