Two persons P and Q can do a job together in 36 days. P is 3 times as efficient as Q. In how many days can Q alone complete the work?

144

P + Q = 36 days,

Given, P is 3 times more efficient than Q, i.e;

                           P  :  Q

 Efficiency            3   :  1

now, (3 + 1) x 36 = 144 units   ..(Total Efficiency × Days = Total work)

⇒ time taken bv Q to complete the whole work by himself = \(\frac{work}{efficincy}\) = \(\frac{144}{1}\) = 144 days.