2025 · Q61
P and Q are two points on a highway, 300 km apart. Two bikers A and B start at the same time from P towards Q. The speed of B is 12 km/h less than that of A. On reaching point Q, biker A immediately returns towards P. He meets B on the road at a place 60 km away from Q. What is the speed of A?
general-mental-abilityquantitative-aptitude
- A38 km/h
- B30 km/h
- C36 km/h
- D35 km/h
Explanation
Let A's speed be v km/h, so B's is (v-12) km/h. A covers 300 km to Q and returns 60 km, travelling 360 km in time 360/v. In that same time B covers 300-60 = 240 km, so v-12 = 240/(360/v) = (2/3)v. Solving v - 12 = (2/3)v gives (1/3)v = 12, so v = 36 km/h.