Exercise :: Area - General Questions
| 1. | The ratio between the length and the breadth of a rectangular park is 3 : 2. If a man cycling along the boundary of the park at the speed of 12 km/hr completes one round in 8 minutes, then the area of the park (in sq. m) is: |
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Answer: Option B Explanation:
Let length = 3x metres and breadth = 2x metres. Then, 2(3x + 2x) = 1600 or x = 160.
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m = 1600 m.
Length = 480 m and Breadth = 320 m.| 2. | An error 2% in excess is made while measuring the side of a square. The percentage of error in the calculated area of the square is: |
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Answer: Option D Explanation: 100 cm is read as 102 cm.
(A2 - A1) = [(102)2 - (100)2] = (102 + 100) x (102 - 100) = 404 cm2.
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| 3. | The ratio between the perimeter and the breadth of a rectangle is 5 : 1. If the area of the rectangle is 216 sq. cm, what is the length of the rectangle? |
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Answer: Option B Explanation:
Then, Area = 216 cm2
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2l + 2b = 5b| 4. | The percentage increase in the area of a rectangle, if each of its sides is increased by 20% is: |
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Answer: Option C Explanation: Let original length = x metres and original breadth = y metres. Original area = (xy) m2.
The difference between the original area = xy and new-area 36/25 xy is = (36/25)xy - xy = xy(36/25 - 1) = xy(11/25) or (11/25)xy
Video Explanation: https://youtu.be/I3jLjLPn1W4 |
| 5. | A rectangular park 60 m long and 40 m wide has two concrete crossroads running in the middle of the park and rest of the park has been used as a lawn. If the area of the lawn is 2109 sq. m, then what is the width of the road? |
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Answer: Option B Explanation: Area of the park = (60 x 40) m2 = 2400 m2. Area of the lawn = 2109 m2.
Let the width of the road be x metres. Then, 60x + 40x - x2 = 291
Video Explanation: https://youtu.be/R3CtrAKGxkc |