Multiple choice

P can do a piece of work in 18 days. Q is 20 percent more efficient than P. Then in how many days three-fourth of the work is completed when both are working simultaneously?

  1. 7 5/13 days

  2. 9 4/7 days

  3. 6 3/22 days

  4. 8 6/17 days

  5. None of these
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

P rate = 1/18. Q rate = 1.2 * (1/18) = 1/15. Combined rate = 1/18 + 1/15 = (5+6)/90 = 11/90. Time for full work = 90/11. Time for 3/4 work = (3/4) * (90/11) = 270/44 = 135/22 = 6 3/22 days.

AI explanation

P's daily work rate is 1/18. Since Q is 20% more efficient, Q's daily work rate is 1.2 divided by 18, which equals 1/15. Their combined daily rate is 1/18 + 1/15 = 11/90. To complete three-fourths of the work, the time required is 3/4 divided by 11/90. This calculation gives 135/22 days, which is written as 6 3/22 days.

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