In one km race A beats B by 4 seconds or 40 metres. How long does B take to run the kilometer?
112 sec
110 sec
101 sec
100 sec
Explanation:
This means, B takes 4 seconds to run 40 metres
$\text{=> B takes }\dfrac{4}{40} = \dfrac{1}{10}\text{ seconds to run 1 metre}$
$\text{=> B takes }\dfrac{1}{10} \times 1000 = 100 \text{ seconds to run 1000 metre}$