Multiple choice

P is four times as efficient as Q. P can complete a work in 45 days less than Q. If both of them work together, then in how many days the work will be completed?

  1. 10

  2. 12

  3. 15

  4. 30
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Since P is 4 times as efficient as Q, P takes 1/4 the time Q takes. Let Q take x days, then P takes x/4 days. Given P takes 45 days less: x - x/4 = 45, so 3x/4 = 45, x = 60. Q takes 60 days, P takes 15 days. Combined rate: 1/60 + 1/15 = 1/60 + 4/60 = 5/60 = 1/12. Together they complete the work in 12 days.

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