P alone can do a work in 13 days, Q alone can do the same work in 39 days, R alone can do the same work in 52 days. They start the work together and completed the work such that P and Q was not working on last 1 day. In how many days (total) was the work completed ?
Answer & explanation
Correct answer: option 3
Let us include their last day work in total work .
P's last day work = + 12
R's last days work = + 3
Total work = 156 + 15 = 171
total work was completed = \(\frac{171}{19}\) = 9 days