DIRECTIONS : Problems based on Area.
5. |
A rectangular field is to be fenced on three sides leaving a side of 20 feet uncovered.If the area of the field is 680 sq.ft, how many feet of fencing will be required? |
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A. 34 |
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B. 40 |
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C. 68 |
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D. 88 |
Solution |
We have:L =20 ft and lb = 680 sq.ft |
b = 34ft |
Length of fencing | = (l + 2b) |
= (20 + 68)ft |
= 88 ft. |
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6. |
A large field of 700 hectares is divided into two parts. The difference of the areas of the two parts is one–fifth of the average o fthe two areas. What is the area of the smaller part in hectares? |
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A. 225 |
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B. 280 |
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C. 300 |
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D. 385 |
Solution |
Let the areas of the two parts be x and (700 - x)hectares | = [x - (700 - x)] |
= 1 / 5 x [x + (700 - x)/ 2] |
= 2x - 700= 70 |
x = 385. |
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7. |
2 metres broad pathway is to be constructed around a rectangular plot on the inside. The area of the plots is 96 sq.m. The rate of construction is Rs. 50 per square metre. Find the total cost of the construction? |
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A. Rs.2400 |
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B. Rs.4000 |
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C. Data inadequate |
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D. None of these |
Solution |
Given lb =96 |
Area of pathway | = [(l-4)(b-4)-lb] |
= 16-4(l+b) |
Which cannot be determined. so, data is inadequate. |
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8. |
A typist uses a sheet measuring 20cm by 30cm lengthwise. If a margin of 2 cm is left on each side and a 3 cm margin on top and bottom, then percent of the page used for typing is |
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A. 40 |
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B. 60 |
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C. 64 |
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D. 72 |
Solution |
Area of the sheet | = (20 x 30 ) cm² |
= 600 cm² |
Area used for typing | = [(20 - 4) x (30 - 6)] cm² |
= 384 cm² |
Required percentage | = (384 / 600 x 100)% |
=64%. |
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