A long distance runner run 9 laps of a 400 metres track everyday. His timings (in min) for four consecutive days are 88, 96, 89 and 87 respectively. On an average, how many metres/minutes does the runner cover ?

A. 17.78 m/min

B. 40 m/min

C. 90 m/min

D. None of these

Answer: Option B

Solution(By Examveda Team)

$$\eqalign{ & {\text{Average speed :}} \cr & = \frac{{{\text{Total distance covered }}}}{{{\text{Total time taken}}}} \cr & = \left( {\frac{{4 \times 9 \times 400}}{{88 + 96 + 89 + 87}}} \right){\text{m/min}} \cr & = \left( {\frac{{14400}}{{360}}} \right){\text{m/min}} \cr & = 40{\text{ m/min}} \cr} $$