A can give 40 metres start to B and 70 metres to C in a race of one kilometre how many metres starts can B give to C in a race of one kilometre ?

Answer: Option C

$$\begin{array}{rl}& \text{A}\text{B}\text{C}\\ & \text{1000}\text{960}\text{930}\end{array}$$
⇒ B can give C a start of 30 metres in a 960 metres race
⇒ 960 units → 30
⇒     1 unit → $$\frac{1}{32}$$
⇒ 1000 units → $$\frac{1000}{32}$$
  = $$31\frac{1}{4}$$ metres