How many seconds will a boy take to run one complete round around a square field of side 79 metres, if he runs at a speed of 4 km/h?

Correct option is D

Given:

Side of square field = 79 m

Speed = 4 km/h

Formula Used:

Perimeter of square = 4 × side

Time = $$\frac{\text{Distance}} {\text{ Speed}}$$​​

Solution:

Perimeter of square field = 4 × 79 = 316 m

Speed in m/s = $$\frac{4 \times 1000}{3600} = \frac{4000}{3600} = \frac{10}{9} m/s$$​​

Time = $$\frac{316}{\frac{10}{9}} = 316\times \frac{9}{10} = 284.4 sec$$​​

Thus, The boy will take 284.3 seconds to complete one round