RBI Assistant Model Paper 9

Let total work be 90 units (LCM)
So, efficiency of A + B = 5 units/days
And efficiency of B + C = 3 units/day
Let efficiency of C = a units/day
So, efficiency of A = 2a units/day
ATQ
⇒ 2a+B = 5 ..... (i)
⇒ B+a = 3 ..... (ii)
From (i) and (ii)
Efficiency of B = 1 unit/day
∴ required time =

90

1

= 90 days