Disha can run 1 km in 2 minutes 30 seconds and Amisha can cover the same distance in 2 minutes 40 seconds. Disha can beat Amisha by distance ___________ .
Answer & explanation
Correct answer: option 4
$\text{Distance}=1\text{ km}=1000\text{ m}.$
$\text{Time taken by Disha}=2\text{ min }30\text{ s}=150\text{ s}.$
$\text{Time taken by Amisha}=2\text{ min }40\text{ s}=160\text{ s}.$
$\text{Speed of Disha}=\frac{1000}{150}=\frac{20}{3}\text{ m/s}.$
$\text{Speed of Amisha}=\frac{1000}{160}=\frac{25}{4}\text{ m/s}.$
$\text{Distance covered by Amisha in }150\text{ s}=\frac{25}{4}\times150=937.5\text{ m}.$
$\text{Distance by which Disha beats Amisha}=1000-937.5=62.5\text{ m}.$
$\text{Disha beats Amisha by }62.5\text{ m}.$