**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**