Question

If A and B together can complete a work in 18 days, A and C together in 12 days and B and C together in 9 days, then in how many days B alone can do the work?
A. 18 days
B. 24 days
C. 30 days
D. 40 days

Answer 1

Answer:

it is correct answer

Explanation:

24 days

(A + B)’s 1 day’s work = \frac{1}{18}

(B + C)’s 1 day’s work = \frac{1}{9}

(C + A)’s 1 day’s work = \frac{1}{12}

On adding all above equations, we get

2 (A +B + C)’s 1 day’s work = \frac{1}{18} + \frac{1}{9} + \frac{1}{12} = \frac{2+4+3}{36} = \frac{9}{36} = \frac{1}{4}

∴ (A + B + C)’s 1 day’s work = \frac{1}{8}

Now, B’s 1 day’s work = (A + B + C)’s 1 day’s work – (A + C)’s 1 day’s work

= \frac{1}{8}-\frac{1}{12}=\frac{3-2}{24}=\frac{1}{24}

Hence B alone can do the work in 24 days. So option [B] is correct answer.

Answer 2

Answer:

B 24 days is correct answers