Multiple choice

Three individuals, Alice, Bob, and Carol, respectively take 25 days, 40 days, and 50 days to complete a project. How many days will it take for Alice to complete the project if she is assisted by Bob and Carol every second day?

  1. 14 days

  2. 16 days

  3. 18 days

  4. 20 days

  5. a
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Alice's rate = 1/25. Bob's rate = 1/40. Carol's rate = 1/50. Combined rate (Alice+Bob+Carol) = (8+5+4)/200 = 17/200. Every two days, the work done is (1/25) + (17/200) = (8+17)/200 = 25/200 = 1/8. To complete 1 project, it takes 8 cycles of 2 days = 16 days.

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