A and B can complete a piece of work in 21 days. A is 7/4 times as efficient…
2019
A and B can complete a piece of work in 21 days. A is 7/4 times as efficient as B. In how many days can A alone complete 100/3% of the work (i.e., one-third of the work)?
Answer: C. 11 — Let B's efficiency be 4 units/day, so A's efficiency is 7 units/day. Together, A and B complete 11 units/day and finish the work in 21 days. Total work = 11 ×…
- A.
13
- B.
22
- C.
11
- D.
17
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Correct answer: C
Let B's efficiency be 4 units/day, so A's efficiency is 7 units/day.
Together, A and B complete 11 units/day and finish the work in 21 days.
Total work = 11 × 21 = 231 units.
One-third of the work = 231/3 = 77 units.
Time taken by A alone = 77/7 = 11 days.
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