R. S. Aggarwal Solutions for Chapter: Time and Distance, Exercise 1: EXERCISE 17A

A train covered the distances of $10 \mathrm{km}, 20 \mathrm{km}$ and $30 \mathrm{km}$ at the speeds of $50 \mathrm{km}/\mathrm{hr}, 60 \mathrm{km}/\mathrm{hr}$ and $90 \mathrm{km}/\mathrm{hr}$ respectively. The average speed of the train over the whole journey is:

A runs twice as fast as $\mathrm{B}$ and $\mathrm{B}$ runs thrice as fast as $\mathrm{C}$. $A$ certain distance was covered by $\mathrm{C}$ in $42$ minutes. How much time will A take to cover this distance?

The ratio of the speeds of $\mathrm{A}$ and $B$ is $3: 4$. In order to reach a destination $\mathrm{A}$ takes $30$ minutes more than $\mathrm{B}$. What is the time taken by $\mathrm{A}$?

A boy is running at a speed of $\mathrm{p} \mathrm{km}/\mathrm{hr}$ to cover$1 \mathrm{km}$ . Due to slippery road, his speed is reduced by $\mathrm{q} \mathrm{km}/\mathrm{hr}$. If he takes r hours to cover this distance, which of the following is true?

An aeroplane started its flight 30 min later than the scheduled time. In order to reach his destination $1500 \mathrm{~km}$ away in time, it increased its speed by $250 \mathrm{~km} / \mathrm{hr}$. His normal speed is

A car covers a certain distance in $8 \mathrm{hours}$. If the speed is increased by $4 \mathrm{km}/\mathrm{hr}$, this distance could be covered in $7\frac{1}{2}$ hours. This distance is______.

A man takes $6 \mathrm{hours}$ to walk to a certain place and riding back. However, he could have gained $2\frac{1}{2} \mathrm{hours}$ , if he had covered both ways by riding. How long would he have taken to walk both ways?

A man cycles from $\mathrm{A}$ to $\mathrm{B}$, a distance of $21 \mathrm{km}$ in $1\mathrm{hr}40 \min$. The road from $\mathrm{A}$ is level for $13 \mathrm{km}$ and then it is uphill to $\mathrm{B}$. The man's average speed on level is $15 \mathrm{km}/\mathrm{hr}$. His average uphill speed is_______.