Question

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

• A. $17.78$
• B. $40$
• C. $90$
• D. $55$

Answer 1

The correct option is B $40$

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