A boy is travelling from his home to school at 3 km/hr and reached 7 min late. Next day he traveled at 6 km/hr and reached 8 min early. Distance between home and school?  Choose one
A) 1.2 km
B) 1.3 km
C) 1.4 km
D) 1.5 km
E) 1.6 km

Rationale: "let the distance be x t 1 = x / 3 hr t 2 = x / 6 hr difference in time = 7 + 8 = 15 = 1 / 4 hr x / 3 - x / 6 = 1 / 4 x / 6 = 1 / 4 x = 1.5 km answer is d"
Answer: D