A, B and C can do a work separately in 20, 35 and 60 days, respectively. They started the work together, but B and C left 8 days and 12 day, respectively, before the completion of the work. In how many days will the work be completed?
A, B and C can do a work separately in 20, 35 and 60 days, respectively. They started the work together, but B and C left 8 days and 12 day, respectively, before the completion of the work. In how many days will the work be completed? Correct Answer 15 days
Given:
Time taken by A = 20 days
Time taken by B = 35 days
Time taken by C = 60 days
B and C left 8 days and 12 days
Formula used:
Work = Time × Efficiency
Calculation:
LCM of 20, 35 and 60 is 420
Efficiency of A = (420/20) = 21
Efficiency of B = (420/35) = 12
Efficiency of C = (420/60) = 7
Now,
Suppose B and C does not leave till the work get completed
Work of B and C for 8 days and 12 days = (12 × 8 + 7 × 12)
⇒ (96 + 84)
⇒ 180
New total work = (420 + 180) = 600
Number of days to complete the whole work by A, B and C = Total work/Efficiency of (A + B + C)
⇒
⇒ 600/40
⇒ 15 days
∴ The required days is 15 days