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A retaining wall with measurements 30m × 12m × 6m was constructed with bricks of dimensions 8cm × 6cm × 6cm. If 60% of the wall consists of bricks, the number of bricks used for the construction is ______ lakhs.
- 30
- 40
- 45
- 75
Correct answer: 45
Solution
Wall volume = 30*12*6 = 2160 m^3; bricks occupy 60% = 1296 m^3. One brick = 0.08*0.06*0.06 = 0.000288 m^3. Number of bricks = 1296/0.000288 = 4,500,000 = 45 lakhs (option 2), not 75.
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