A student walks from his house at speed of $2\frac{1}{2}$ km/hour and reaches his school late by 6 min. Next day, he increases his speed by 1 km/hour and reaches 6 min before school time. How far is the school from his house?

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.

Given below are two statements based on the following:

A motor boat can travel 30 km upstream and 28 km downstream in 7 hours. It can travel 21 km upstream and return in 5 hours.

Statement I: Speed of the boat in still water is 12 km per hour.

Statement II: Speed of the stream is 4 km per hour.

In the light of the above statements, choose the correct answer from the options given below:

Ram and Shyam run a race between points $A$ and $B, 5 \mathrm{~km}$ apart. Ram starts at 9 AM from A at a speed of $5 \mathrm{~km} / \mathrm{hr}$, reaches $B$ and returns to $A$ at the same speed. Shyam starts at $9: 45 \mathrm{AM}$ from $\mathrm{A}$ at a speed of $10 \mathrm{~km} / \mathrm{hr}$, reaches $B$ and comes back to $A$ at the same speed.

At what time do Ram and Shyam meet each other ?

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 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

Three rings complete 60, 36 and 24 revolutions in a minute. They start from a certain point in their circumference down wards. By what time they come together again in the same position?