(A) 15,25,35,45
(B) 20,30,40,120
(C) 20,30,40,50
(D) 20,25,30,60
Correct Option is: B
Time taken by (P + Q) to finish the job = 24days.
(P + Q)’s 1 day’s job = 1/24
Time taken by (Q +R) to finish the job = 30days.
(Q + R)’s 1 day’s job = 1/30
Time taken by (R + P) to finish the job = 40 days.
(R + P)’s 1 day’s job = 1/40
Therefore, 2(P + Q + R)’s 1 day’s job = (1/24+1/30+1/40)
=(5+4+3)/120
=12/120=1/10
⇒ (P + Q + R)’s 1 day’s job = ½*1/10 =1/20
Therefore, P, Q, R together can finish the job in 20 days.
Now, P’s 1 day’s job
= {(P + Q + R)’s 1 day’s job } – {(Q + R)’s 1 day’s job }
= (1/20 -1/30)=2/60=1/30
Hence, P alone can finish the job in 30 days.
Q’s 1 day’s work
{(P + Q + R)’s 1 day’s job } – {(R + P)’s 1 day’s job
= (1/20 -1/40)=1//40
Hence, Q alone can finish the job in 40 days.
R’s 1 days work
= {(P + Q + R)’s 1 day’s job } – {(P + Q)’s 1 day’s job }
= (1/20 -1/24)=1/120
Hence, R alone can finish the job in 120 days.