# In How Many Days B Alone could do it, If

A can do a certain work in the same time in which B and C together can do it. If A and B together could do it in 10 days and C alone in 50 days, then B alone could do it in:

- 25 days
- 20 days
- 15 days
- None of the above

**Answer: (1) 25 days.
Explanation:-**

(A + B) can do a work = 10 days

Therefore, (A + B) can do work in a day = 1/10

C can do a work = 50

Therefore, C can do work in a day = 1/50

(A + B + C) can do work in a day = 1/10 + 1/50

= 6/50 = 3/50 ……..(1)

A can do work = (B + C) can do work ..(2)

From (1) & (2),

2 x (A can do work in a day) = 3/25

A can do work in a day = 3/2 x 25 = 3/50

Therefore, B can do work in a day = 1/10 – 3/50

= 2/50 = 1/25

Hence, B alone can do work complete in 25 days.