Mathematics
NULL
Medium
Question
A rectangular field is 30 m long and 20 m broad. How deep should it be dug so that the earth taken out (increased by 10%) forms a platform 8 m × 5.5 m × 1.5 m?
A
12 cm
B
10 cm
✓ Official correct answer
C
18 cm
D
24 cm
Community credibility
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A
12 cm
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B
10 cm
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C
18 cm
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D
24 cm
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Explanation
Platform volume = 66 m³. Pit volume × 1.1 = 66 ⇒ pit = 60 m³. Depth = 60/(30×20) = 0.1 m = 10 cm.