How much time will a horse take to run around a square field of side 175 m if it runs at the speed of 15 km/hr?

Side of the square field = 175 m

Perimeter of the square field = 4 x 175 = 700 m

$$\therefore\ $$Distance to be travelled by the horse = 700 m

Speed of the horse = 15 km/hr = $$15\times\frac{5}{18}$$ m/sec = $$\frac{25}{6}$$ m/sec

$$\therefore\ $$Time taken by the horse to run around the square field = $$\frac{\text{Distance travelled}}{\text{Speed}}$$ = $$\frac{700}{\frac{25}{6}}$$ = $$\frac{700\times6}{25}$$ = $$168\sec$$

Hence, the correct answer is Option D