SSC CGL 2018 PYQ — Question 60

SSC CGL Tier II Quant - 09/03/2018 • Quantitative Aptitude • Q60

Working together A and B can do a job in 36 days, B and C in 10 days and all three together in 9 days. In how many days can B alone do the job?

Show answer & explanation

Correct answer: D

Explanation

  The correct answer is option 4 i.e. 60

Understanding

Application

Working together A and B can do a job in 36 days, B and C in 10 days and all three together in 9 days.

Suppose total work = 180 units (LCM of 36, 10 and 9)

So,

Efficiency of (A + B) = 180/36 = 5

Efficiency of (B + C) = 180/10 = 18

Efficiency of (A + B + C) = 180/9 = 20

Hence,

Efficiency of C = 20 – 5 = 15

Efficiency of B = 18 – 15 = 3

Hence,

Time in which B alone can complete = 180/3 = 60 days