S.chand class 6 Mathematics Chapter 11 Exercise 11

 Exercise 11

Question 1

1. A motorist travelled at a speed of $70 \mathrm{~km} / \mathrm{hr}$. At this speed how far could he travel in 7 hours.

2. Find the time taken by a bus to travel $280 \mathrm{~km}$ at a speed of $80 \mathrm{~km} / \mathrm{hr}$.

3. Express the following speeds in $\mathrm{km} / \mathrm{hr}$.

(i) $12 \frac{1}{2} \mathrm{~m} / \mathrm{s}$

(ii) $20 \mathrm{~m} / \mathrm{s}$

(iii) $270 \mathrm{~m}$ in $12 \mathrm{sec}$

(iv) $200 \mathrm{~m}$ in $36 \mathrm{sec}$

4. Express the following speeds in $\mathrm{m} / \mathrm{s}$ (metres per second).

(1) $60 \mathrm{krnhr}$

(ii) $90 \mathrm{~km} / \mathrm{hr}$

(iii) $12.6 \mathrm{~km} / \mathrm{hr}$

5. A car moves at a speed of $54 \mathrm{~km} / \mathrm{hr}$. What is the speed of the car in metres per second?

6. An athlete runs a 200 metres race in 24 seconds. What is his speed in $\mathrm{km} / \mathrm{hr}$ ?

7. An aeroplane travelled $4320 \mathrm{~km}$ in $6 \mathrm{hr}$. Find its speed in (i) $\mathrm{km} / \mathrm{hr}$ (ii) $\mathrm{m} / \mathrm{s}$.

8. The distance between two cities is $380 \mathrm{~km}$. A train takes 6 hours $40 \mathrm{minutes}$. the speed of the train.

9. A tourist bus left town $A$ and travelled at an average speed of $85 \mathrm{~km} / \mathrm{hr}$ to town $B$ which was $340 \mathrm{~km}$ away if it reached town $B$ at $1: 15$ p.m., at what time did it start?

10. A motorist travelled a distance of $150 \mathrm{~km}$ at a speed of $60 \mathrm{~km} / \mathrm{hr}$. He left at 11:30 a.m. and stopped for 45 min on the way. At what time did he reach his destination.

11. Shyam and Arikur both use cars to go to their offices. Shyam covers a distance of $16 \mathrm{~km}$ in $30 \mathrm{minutes}$ while Ankur covers a distance of $12 \mathrm{~km}$ in 20 minutes. Which of the two drives faster?

12.Lily drove from Town $X$ to Town $Y$ at an average speed of $78 \mathrm{~km} / \mathrm{hr}$. After $1 \frac{1}{5}$ hours, she completed $\frac{3}{7}$ of her journey. What is the distance between Town $X$ and Town $Y$ ?

13. Aditya left his house at $9.20$ a.m. and travelled at $75 \mathrm{~km} / \mathrm{hr}$. His brother left later and travelled along the same road at $90 \mathrm{~km} / \mathrm{hr}$. They both arrived at the same destination at $3: 20$ p.m. At what time did Aditya's brother leave home?

14. Meenu drives her car for $1 \frac{1}{2}$ hours with a constant speed of $66 \mathrm{~km} / \mathrm{hr}$ and then for another 45 minutes with a constant speed of $80 \mathrm{~km} / \mathrm{hr}$. What was her average speed?

15. An aeroplane travels distances of $2500 \mathrm{~km}, 1200 \mathrm{~km}$ and $500 \mathrm{~km}$ at the rate of $500 \mathrm{~km} / \mathrm{hr}$, $400 \mathrm{~km} / \mathrm{hr}$ and $250 \mathrm{~km} / \mathrm{h}$ respectively. Find the average speed of the plane.

16. For a race Manish ran at a speed of $6 \mathrm{~m} / \mathrm{s}$ for 10 seconds. He ran a further $40 \mathrm{~m}$ at a speed of $8 \mathrm{~m} / \mathrm{s}$. What is his average speed for the race in $\mathrm{km} / \mathrm{h}$ ?

17. Rachit took 4 hours to complete the last $\frac{1}{4}$ part of a journey at an average speed of $55 \mathrm{~km} / \mathrm{hr}$. His average speed for the whole journey is $60 \mathrm{~km} / \mathrm{hr}$. How long will it take to cover the first $\frac{3}{4}$ part of the journey?

18. A train $280 \mathrm{~m}$ long is moving at a speed of $60 \mathrm{~km} / \mathrm{hr}$. What is the time taken by it to cross a platform $220 \mathrm{~m}$ long?

19. A train is running at a speed of $90 \mathrm{~km} / \mathrm{hr}$. If it crosses a signal in 10 seconds. Find the length of the train in metres.

20. A train $150 \mathrm{~m}$ long passes a tree in 12 seconds. How long will it take to pass a tunnel $250 \mathrm{~m}$ long? 

Multiple Choice Questions (MCQs)

Tick (✔) the correct option.

21. Which of the following is the slowest speed?

(a) $6 \frac{1}{2} \mathrm{~km} / \mathrm{hr}$

(b) $90 \mathrm{~m} / \mathrm{min}$

(c) $\frac{1}{2} \mathrm{~km} / \mathrm{min}$

(d) $3 \mathrm{~km} / \mathrm{sec}$

22. A car takes 30 minutes to travel from town A to town B if it travels at a speed of $50 \mathrm{~km} / \mathrm{hr}$. If its speed is increased by $20 \%$, how long will it take to travel from town $\mathrm{A}$ to town $\mathrm{B}$ ?

(a) $10 \mathrm{~min}$

(b) $20 \mathrm{~min}$

(c) $25 \mathrm{~min}$

(d) $15 \mathrm{~min}$