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) $15 \mathrm{~min}$
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