Page 208 - New Medley 5 Semester 1

Example 12: The cost of 1 L of petrol is `73.74. Find the cost of 7.5 L
of petrol.

7 3 . 7 4 → 2 places
Solution:  Cost of 1 L of petrol = `73.74
× 7.5 → 1 place

∴ Cost of 7.5 L of petrol 3 6 8 7 0
5 1 6 1 8
= `73.74 × 7.5
5 5 3.0 5 0 ← 3 places

= `553.05
Thus, the cost of 7.5 L of petrol is `553.05.

EXERCISE 5.4

A. Multiply the following.

1. 2.27 by 2 2. 3.967 by 4 3. 42.18 by 6

4. 57.5 by 12 5. 69.02 by 25 6. 0.725 by 32

B. Find the product of the following by shifting the decimal point.

1. 4.97 × 10 2. 21.325 × 100 3. 9.335 × 1000 4. 41.6 × 100
5. 524.3 × 1000 6. 6.873 × 10 7. 7.28 × 1000 8. 82.1 × 10

C. Find the product of each of the following.
1. 2.3 × 3.2 2. 8.34 × 1.8 3. 4.65 × 2.68

4. 8.5 × 0.6 5. 0.923 × 2.85 6. 1.235 × 0.008

D. Insert the decimal point at the correct position in the product.

1. 1.2 × 3.6 = 432 2. 1.65 × 4.48 = 73920

3. 0.635 × 1.5 = 9525 4. 3.251 × 0.69 = 224319

5. 0.2 × 0.4 × 0.1 = 8 6. 1.3 × 0.15 × 0.06 = 1170

E. Solve the following word problems.

1. The cost of potatoes is `24.8 per kg. Find the cost of 25 kg of potatoes.

2. A bottle can hold 0.75 L of milk. How much milk 12 such bottles can
hold?

3. A park is 40.5 m long and 24.14 m wide. Find the area of the park.

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