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And, the expenditures on transportation = ` 8 × 40000 = `5000
Hence, his expenditure on the food and transportation are `12000 and `5000 respectively.
1 1
Example 21: A bike covers 55 km in an hour. How much distance will it cover in 4 hours?
5 6
1
Solution: Since, the distance covered by the bike in 1 hour = 55 km
5
1 1 1 276 25 = (
×
\ In 4 hours, the bike will cover the distance = 55 × 4 km = × km 46 5)km
6 5 6 5 6
= 230 km
1
Thus, the bike will cover 230 km in 4 hours.
6
1
2
Example 22: The cost of 5 metres of rope is `25 . Find its cost per metre.
3 2
1
Solution: Given, the cost of 5 2 metres of rope is `25 .
3 2
3
1
\ Cost of 1 metre of rope = ` 25 ÷ 5 2 ` 51 ÷ 17 = ` 51 × 17 = ` 9 = ` 4 1
=
3
3
2
2
2
2
2
1
Thus, the cost of 1 metre of rope is `4 .
2
Practice Time 1F
1
1. On Saturday, Raj practised Maths for 1 hours, read an English literature book for
4
1 3
1 hours and did map work for 2 hours. How much time did he spend studying?
3 5
1 3
2. A drum full of wheat weighs 31 6 kg. If the empty drum weighs 11 4 kg, find the
weight of wheat in the drum.
1
3. How much distance will a train cover in 4 hours if it maintains a constant speed
1 3
of 70 km/h?
4
1 1
4. The length of a rectangular plot is 7 m and its breadth is 6 m. Find its area.
4 4
−16 −14
5. The product of two rational numbers is . If one of the numbers is , find the other.
35 15
5 9
6. A number has been divided into two parts, i.e., 14 and 14 . If the difference of these parts is 24,
find the number.
7
7. The product of two rational numbers is −3 . If one of the numbers is , then find the other number.
2 3
1
8. A sports car covers a distance of 480 km in 2 hours. Find the speed of the sports car. Also, find
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the time taken by the sports car to cover a distance of 800 km.
29 Rational Numbers
