Multiple choice

P can do (\frac{2}{5})th part of a work in 12 days, while Q can do (\frac{3}{4})th of the same work in 15 days. In how many days both will complete the work if they worked together?

  1. 10 days

  2. 12 days

  3. 15 days

  4. 18 days

  5. 24 days
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

P does 2/5 work in 12 days, so P's rate is (2/5)/12 = 1/30 per day, meaning P takes 30 days alone. Q does 3/4 work in 15 days, so Q's rate is (3/4)/15 = 1/20 per day, meaning Q takes 20 days alone. Together their rate is 1/30 + 1/20 = 5/60 = 1/12 per day, so they complete the work in 12 days. Option B is correct.

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