If B is 50% less efficient than A and they finish a job in 18 days together, A alone would take?
Correct answer: A. 27
- A. 27
- B. 30
- C. 36
- D. 24
Explanation
The correct answer is 27 days. To solve this, first understand the efficiency relationship: B is 50% less efficient than A, so if A's work rate is 2 units/day, B's is 1 unit/day. Together, their combined work rate is 3 units/day. Given they complete the job in 18 days together, the total work done is 3 units/day × 18 days = 54 units. When A works alone, he completes the work at his own rate of 2 units/day. Therefore, the time taken by A alone is 54 ÷ 2 = 27 days. The other options are incorrect as they misinterpret the efficiency or the total work calculation.
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24 - Correct. C does double the work → C = 2 units/day, A = 1 → If C finishes in 12, total = 24 units → A = 1/day → 24 days.