In a flat race, A beats B by 15 m and C by 29 m. When B and C run over the same course together, B wins by 15 m. The length of the course is

A person travels three equal distances at a speed of 'a' $\mathrm{km} / \mathrm{hr}$, 'b' $\mathrm{km} / \mathrm{hr}$ and ' $c$ ' $\mathrm{km} / \mathrm{hr}$ respectively. What is the average speed for the whole journey?

Two persons A and B start from the same point to travel from Chandigarh to Ambala. The distance between Chandigarh and Ambala is $60 \text{ km}$. Speed of A is $4 \text{ km/hr}$ slower than B. B, when reaches Ambala, starts back via the same route without taking any rest and meets A who was still $12 \text{ km}$ away from Ambala. Find the speed of A.

Aman takes half the time in rowing a certain distance downstream than upstream.
Statement (I): Ratio of the speed of the boat in still water to the speed of the water current is 2: 1.
Statement (II): If the speed of the boat in still water is 6 km per hour, then the speed of the water current is 2 km per hour.
Choose the most appropriate answer from the options given below.

A boy covers a certain distance on a toy train. If the train moved 4 kmph faster, it would take 30 minutes less. If it moved 2 kmph slower, it would have taken 20 minutes more. The distance is

A train with 90 kmph crosses a bridge in 36 s. Another train 100 m shorter crosses the same bridge at 45 kmph. The time taken by the second train to cross the bridge will be

A man rows 20 km upstream and back again to the starting point in 110 minutes. If the speed of the stream is 2 kmph, then the speed of rowing in still water is