Question

Question #23502

Answer 1

For `10` seconds.

Explanation:

The relationship between distance(`d`), speed(`v`) and time (`t`) is `d=vt`.
Therefore, `t=d/v` is the formula you should use in the question.

Since `9.1` km`=9100` m, the time required to finish for driver 1 is `t_1=9100/65 = 140` (s). Driver 2 finishes in `t_2=9100/70=130` (s).

Driver 2 have to wait `t_1-t_2=140-130=10` seconds.