Question
A can paint a house in 55 days and B can do it 66 days. Along with C, they did the job in 12 days only. Then, C alone can do the job in how many days?
A. 33
B. 24
C. 44
D. 20
Answer: A – 33
Solution:
A’s one-day work = 1/55
B’s one-day work = 1/66
(A+B)’s one-day work =1/55+1/66= 6+5/330=11/330=1/30
C’s one-day work = 1/x
A+B+C together finished the work in 12 days
(A+B+C )’s one-day work
(12/30)+12/x=1
12x+360=30x
360= 18x
x=20
Ans. C alone takes 20 days to complete the work