A and B run a race of 960 m. If A gives a start of 96 m to B, he defeats him by 12 sec and if A gives a start of 288 m to B, he loses by 4 sec. What is the speed of B in m/sec?

12 16 18 24

12

Let the speed of B = x m/s ATQ, (time taken by A in both case) ⇒ \(\frac{960 - 96}{x}\) - 12 = \(\frac{960 - 288}{x}\) + 4 ⇒ \(\frac{864}{x}\) - \(\frac{672}{x}\) = 16 ⇒ \(\frac{192}{x}\) = 16 ⇒ x = \(\frac{192}{16}\) ⇒ x = 12 m/sec.