A student goes to school at the rate of 21/2 km/hr and reaches 6 min late. If he travels at the speed of 3 km/hr, he is 10 min early. The distance (in km) between the school and the house is :

Answer: Option B

Solution

Answer: Option B

Solution:

= 6 - 5 = 1 unit → $$\frac{16}{60}$$
15 units → $$\frac{16}{60}$$ × 15 = 4
∴ Required distance = 4 km