P is 20 percent more efficient than Q. P alone can do a work in 2 days less…
2021
P is 20 percent more efficient than Q. P alone can do a work in 2 days less than Q alone. In how many days can they do the work together?
- A.
40
- B.
54/11
- C.
60/11
- D.
53/9
Attempted by 13 students.
Show answer & explanation
Correct answer: C
Let Q take T days, so P takes T - 2 days.
Efficiency ratio P:Q = 120:100 = 6:5.
Since time is inversely proportional to efficiency, the time ratio P:Q = 5:6.
Set up the equation: (T - 2) / T = 5 / 6.
Solving gives 6T - 12 = 5T, so T = 12 days for Q, and 10 days for P.
Combined rate = (1/10) + (1/12) = (6+5)/60 = 11/60.
Total time = 60/11 days.
Final Answer: Option 3