Question: A and B together can complete a piece of work in 18 days, B and C in 24 days and A and C in 36 days. In how many days will all of them together complete the work?
Options:
A) 16 days
B) 15 days
C) 12 days
D) 10 days
Show Answer
Answer:
Correct Answer: A
Solution:
- Given, time taken by (A + B) = 18 days
(A + B)’s 1 day’s work $ =\frac{1}{18} $
(i)
Similarly, (B + C)’s 1 day’s work $ =\frac{1}{24} $
(ii)
(A + C)’s 1 day’s work $ =\frac{1}{36} $
(iii)
On adding Eqs. (i), (ii) and (iii), we get
2 (A + B + C)’s 1 day’s work
$ =\frac{1}{18}+\frac{1}{24}+\frac{1}{36}=\frac{4+3+2}{72}=\frac{1}{8} $
$ \therefore $ (A + B + C)’s 1 day’s work $ =\frac{1}{16} $
$ \therefore $ A, B and C together will complete the work 16 days.