(A) 2:5
(B) 3:4
(C) 1:2
(D) 2:3
Correct Option is: C
Efficiency of P and Q= 1/30 per day ___________1
⇒ Efficiency of Q and R = 1/40 per day_________2
⇒ Efficiency of R and P = 1/40 per day _________3
Taking equation 2 and 3 together
⇒ Q + R = 1/40 and R + P = 1/40
⇒ R and 1/40 will be removed. Hence P = Q
⇒ Efficiency of P = Q =1/60
⇒ Efficiency of R = 1/40-1/60=1/120
⇒ P can do the job in 60 days and R can do the job in 120 days he they work alone.
⇒ Ratio of number of days in which P and R can complete the job 1:2