Multiple choice

Kim is four times as efficient as Kong and Kong is twice as efficient as King. If they take 4 days to complete the work by working together, then how many days does Kim take to complete the whole work alone?

  1. 6.5 days

  2. 6 days

  3. 5 days

  4. 5.5 days
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Let King's efficiency be 1 unit/day. Kong = 2 units/day. Kim = 4 * 2 = 8 units/day. Total efficiency = 1 + 2 + 8 = 11 units/day. Total work = 11 * 4 = 44 units. Kim's time = 44 / 8 = 5.5 days.

AI explanation

Let King's efficiency be 1 unit per day, making Kong's efficiency 2 units per day and Kim's efficiency 8 units per day. Their combined efficiency is 11 units per day, and since they complete the work in 4 days, the total work is 44 units. Kim alone works at 8 units per day, so the time she takes is 44 divided by 8, which equals 5.5 days.

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