Worker A is twice as efficient as Worker B. Working together, they complete a job in 14 days. In how many days can Worker A alone complete the entire job?
Answer and explanation
Correct answer: C. 21 days
- Step 1: Let B's daily work rate be 1 unit/day, then A's rate is 2 units/day. Combined rate = 3 units/day. Step 2. Total work = 14 days 3 units/day = 42 units. Time for A alone = 42 / 2 = 21 days. Answer: 21 days. Why not the others:* 28 days uses wrong ratio; 35 days computes B's rate partially; 42 days is time required for B alone (42/1).
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