Selina Textbook Solutions: Idea of Speed, Distance and Time | Mathematics Class 6 ICSE PDF Download

 Page 1


EXERCISE 17(A) 
Question 1. 
A train covers 51 km in 3 hours. Calculate its speed. How far does the train go in 30 
minutes? 
Solution: 
Given : Distance = 51 km 
Time = 3 hours 
 
Question 2. 
A motorist travelled the distance between two towns, which is 65 km, in 2 hours and 10 
minutes. Find his speed in metre per minute. 
Solution: 
Distance between two towns = 65 km 
Time taken = 2 hr 10 min 
 
 
Question 3. 
A train travels 700 metres in 35 seconds. What is its speed in km/h? 
Page 2


EXERCISE 17(A) 
Question 1. 
A train covers 51 km in 3 hours. Calculate its speed. How far does the train go in 30 
minutes? 
Solution: 
Given : Distance = 51 km 
Time = 3 hours 
 
Question 2. 
A motorist travelled the distance between two towns, which is 65 km, in 2 hours and 10 
minutes. Find his speed in metre per minute. 
Solution: 
Distance between two towns = 65 km 
Time taken = 2 hr 10 min 
 
 
Question 3. 
A train travels 700 metres in 35 seconds. What is its speed in km/h? 
Solution: 
Distance = 700 m 
Time taken = 35 sec 
 
Question 4. 
A racing car covered 600 km in 3 hours 20 minutes. Find its speed in metre per second. 
How much distance will the car cover in 50 sec? 
Solution: 
Distance covered = 600 km 
Time taken = 3 hr 20 min 
 
= Speed x Time 
= 50 x 50 m = 2500 m or 2.50 km 
Question 5. 
Rohit goes 350 km in 5 hours. Find : 
(i) his speed 
(ii) the distance covered by Rohit in 6.2 hours 
(iii) the time taken by him to cover 210 km. 
Solution: 
Distance covered = 350 km 
Page 3


EXERCISE 17(A) 
Question 1. 
A train covers 51 km in 3 hours. Calculate its speed. How far does the train go in 30 
minutes? 
Solution: 
Given : Distance = 51 km 
Time = 3 hours 
 
Question 2. 
A motorist travelled the distance between two towns, which is 65 km, in 2 hours and 10 
minutes. Find his speed in metre per minute. 
Solution: 
Distance between two towns = 65 km 
Time taken = 2 hr 10 min 
 
 
Question 3. 
A train travels 700 metres in 35 seconds. What is its speed in km/h? 
Solution: 
Distance = 700 m 
Time taken = 35 sec 
 
Question 4. 
A racing car covered 600 km in 3 hours 20 minutes. Find its speed in metre per second. 
How much distance will the car cover in 50 sec? 
Solution: 
Distance covered = 600 km 
Time taken = 3 hr 20 min 
 
= Speed x Time 
= 50 x 50 m = 2500 m or 2.50 km 
Question 5. 
Rohit goes 350 km in 5 hours. Find : 
(i) his speed 
(ii) the distance covered by Rohit in 6.2 hours 
(iii) the time taken by him to cover 210 km. 
Solution: 
Distance covered = 350 km 
Time taken = 5 hours 
 
Question 6. 
A boy drives his scooter with a uniform speed of 45 km/h. Find : 
(i) the distance covered by him in 1 hour 20 min. 
(ii) the time taken by him to cover 108 km. 
(iii) the time taken to cover 900 m. 
Solution: 
Speed of the scooter = 45 km/h 
 
 
Page 4


EXERCISE 17(A) 
Question 1. 
A train covers 51 km in 3 hours. Calculate its speed. How far does the train go in 30 
minutes? 
Solution: 
Given : Distance = 51 km 
Time = 3 hours 
 
Question 2. 
A motorist travelled the distance between two towns, which is 65 km, in 2 hours and 10 
minutes. Find his speed in metre per minute. 
Solution: 
Distance between two towns = 65 km 
Time taken = 2 hr 10 min 
 
 
Question 3. 
A train travels 700 metres in 35 seconds. What is its speed in km/h? 
Solution: 
Distance = 700 m 
Time taken = 35 sec 
 
Question 4. 
A racing car covered 600 km in 3 hours 20 minutes. Find its speed in metre per second. 
How much distance will the car cover in 50 sec? 
Solution: 
Distance covered = 600 km 
Time taken = 3 hr 20 min 
 
= Speed x Time 
= 50 x 50 m = 2500 m or 2.50 km 
Question 5. 
Rohit goes 350 km in 5 hours. Find : 
(i) his speed 
(ii) the distance covered by Rohit in 6.2 hours 
(iii) the time taken by him to cover 210 km. 
Solution: 
Distance covered = 350 km 
Time taken = 5 hours 
 
Question 6. 
A boy drives his scooter with a uniform speed of 45 km/h. Find : 
(i) the distance covered by him in 1 hour 20 min. 
(ii) the time taken by him to cover 108 km. 
(iii) the time taken to cover 900 m. 
Solution: 
Speed of the scooter = 45 km/h 
 
 
Question 7. 
I travel a distance of 10 km and come back in 2 hours. What is my speed? 
Solution: 
Total distance covered = 10 km + 10 km = 20 km 
 
Question 8. 
A man walks a distance of 5 km in 2 hours. Then he goes in a bus to a nearby town, 
which is 40 km, in further 2 hours. From there, he goes to his office in an autorickshaw, 
a distance of 5 km, in  hour. What was his average speed during the whole journey? 
Solution: 
Distance of 5 km travelled on foot in 2 hours 
Distance of 40 km travelled by bus in 2 hours 
Distance of 5 km travelled by Rickshaw in  hour 
Total distance covered = 5 + 40 + 5 = 50 km 
 
Question 9. 
Jagan went to another town such that he covered 240 km by a car going at 60 kmh
-1
. 
Then he covered 80 km by a train, going at 100 kmh
-1
 and the rest 200 km, he covered 
by a bus, going at 50 kmh
-1
. What was his average speed during the whole journey? 
Solution: 
Distance covered 240 km by car with speed 60 km/h 
Distance covered 80 km by train with speed 100 km/h 
and rest distance covered 200 km by bus with speed 50 km/h 
Page 5


EXERCISE 17(A) 
Question 1. 
A train covers 51 km in 3 hours. Calculate its speed. How far does the train go in 30 
minutes? 
Solution: 
Given : Distance = 51 km 
Time = 3 hours 
 
Question 2. 
A motorist travelled the distance between two towns, which is 65 km, in 2 hours and 10 
minutes. Find his speed in metre per minute. 
Solution: 
Distance between two towns = 65 km 
Time taken = 2 hr 10 min 
 
 
Question 3. 
A train travels 700 metres in 35 seconds. What is its speed in km/h? 
Solution: 
Distance = 700 m 
Time taken = 35 sec 
 
Question 4. 
A racing car covered 600 km in 3 hours 20 minutes. Find its speed in metre per second. 
How much distance will the car cover in 50 sec? 
Solution: 
Distance covered = 600 km 
Time taken = 3 hr 20 min 
 
= Speed x Time 
= 50 x 50 m = 2500 m or 2.50 km 
Question 5. 
Rohit goes 350 km in 5 hours. Find : 
(i) his speed 
(ii) the distance covered by Rohit in 6.2 hours 
(iii) the time taken by him to cover 210 km. 
Solution: 
Distance covered = 350 km 
Time taken = 5 hours 
 
Question 6. 
A boy drives his scooter with a uniform speed of 45 km/h. Find : 
(i) the distance covered by him in 1 hour 20 min. 
(ii) the time taken by him to cover 108 km. 
(iii) the time taken to cover 900 m. 
Solution: 
Speed of the scooter = 45 km/h 
 
 
Question 7. 
I travel a distance of 10 km and come back in 2 hours. What is my speed? 
Solution: 
Total distance covered = 10 km + 10 km = 20 km 
 
Question 8. 
A man walks a distance of 5 km in 2 hours. Then he goes in a bus to a nearby town, 
which is 40 km, in further 2 hours. From there, he goes to his office in an autorickshaw, 
a distance of 5 km, in  hour. What was his average speed during the whole journey? 
Solution: 
Distance of 5 km travelled on foot in 2 hours 
Distance of 40 km travelled by bus in 2 hours 
Distance of 5 km travelled by Rickshaw in  hour 
Total distance covered = 5 + 40 + 5 = 50 km 
 
Question 9. 
Jagan went to another town such that he covered 240 km by a car going at 60 kmh
-1
. 
Then he covered 80 km by a train, going at 100 kmh
-1
 and the rest 200 km, he covered 
by a bus, going at 50 kmh
-1
. What was his average speed during the whole journey? 
Solution: 
Distance covered 240 km by car with speed 60 km/h 
Distance covered 80 km by train with speed 100 km/h 
and rest distance covered 200 km by bus with speed 50 km/h 
Total distance covered = (240 + 80 + 200) km = 520 km 
 
 
Question 10. 
The speed of sound in air is about 330 ms
-1
. Express this speed in kmh
-1
. How long will 
the sound take to travel 99 km? 
Solution: 
Speed of sound in air = 330 m/sec 
 
EXERCISE 17(B) 
Question 1. 
A train 180 m long is running at a speed of 90 km/h. How long will it take to pass a 
railway signal?