We know that Time is inversely proportional to Efficiency
Here given time ratio of P & P+Q as
P/P+Q = 150/100 = 3:2
Efficiency ratio of P & Q as
P:Q = 2:1 ....(1)
Given Efficiency ratio of Q & R as
Q:R = 3:1 ....(2)
From (1) & (2), we get
P:Q:R = 6:3:1
P alone can finish the work in
22.5(3+1)/6 = 15 days.
