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The cost of levelling a circular field at 50 paise per square metre is Rs. 7700. The cost (in Rs.) of putting up a fence all round it at Rs. 1.20 per metre is (Use π = 22/7)
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- Rs. 132
- Rs. 264
- Rs. 528
- Rs. 1056
- Rs. 132
Correct Option: C
Area of circular field
| = | |
| Rate per square metre |
| = |  |  | sq. metre | |
| 2 | ||||
= (7700 × 2) sq. metre
= 15400 sq. metre
If radius of field = r metre then, pr² = 15400
| ⇒ | r² = 15400 | |
| 7 |
| ⇒ r² = | = 7 × 700 | |
| 22 |
⇒ r = √7 × 7 × 100 = 70 metre
∴ Circumference of circular field = 2πr metre
| = 2 × | × 70 = 440 meter | |
| 7 |
∴ Total expenditure fencing = Rs. (440 × 1.2) = Rs. 528
