Question

A runs as slow as he can in the first lap. In what time should A run the second lap to make the average speed as twice the speed of the first lap.​

Answer 1

let take t time to  the first lap which was d meter long.

speed in first lap = d/t

time taken in 2nd lap =T

let the average speed  = total distance / total time =2d/(t+T)

given

2d/t=2d/(t+T)

T=0 ;

a should run the 2nd lap in 0 sec  , with infinite speed .