Correct Answer - Option 1 : 22.5 days
Given:
A and C together take 15 days
and A, B and C together take 9 days
Formula used:
Efficiency = Work/(Time taken)
Calculation:
Total work = LCM of 9 and 15 = 45 units
Efficiency of (A + C) = 45/15 = 3 units/day
and efficiency of (A + B + C) = 45/9 = 5 units/day
So, efficiency of B = (5 - 3) units\day
⇒ 2 units/day
Now, B alone takes = (45 units)/(2 units/day)
⇒ (45/2) days
⇒ 22.5 days
∴ B alone takes 22.5 days to complete the work.
