Question

find average speed when person travel equal distance at speed of 14m/s,21m/s,28m/s respectively

Answer 1

Let the equal distance traveled in each case be x.

Time taken while moving at 14 m/s = $\frac{x}{14}$

Time taken while moving at 21 m/s = $\frac{x}{21}$

Time taken while moving at 28 m/s = $\frac{x}{28}$

Total time taken = $\frac{x}{14} + \frac{x}{21}+ \frac{x}{28}$

Total time taken = $\frac{(6 + 4 + 3)x}{84}$

Total time taken = $\frac{13x}{84}$

Total distance covered = x + x + x = 3x

Average speed = $\frac{Distance}{time}$

Average speed = $\frac{3x \times 84}{13x}$

Average speed =  19.384 m/s

Hence, the average speed of the person is 19.384 m/s