M and R together can do a work in 20 days. R and P together can do the same work in 30 days. P and M together can do the same work in 60 days. Working together, how much part of work can they do in 5 days?
Show answer & explanation
Correct answer: B
Explanation
Given:
M + R ⇒ 20 days
R + P ⇒ 30 days
P + M ⇒ 60 days
M + R = 1/20
R + P = 1/30
P + M = 1/60
Upon adding:
2(M + R + P) = 1/20 + 1/30 + 1/60
= (3 + 2 + 1)/60 = 6/60 = 1/10
M + R + P = 1/20
Work done in 5 days = 5 × (1/20) = 1/4