22.
|
A can do a piece of work in 4 hours; B and C together can do it in 3 hours, while A and C together can do it in 2 hours. How long will B alone take to do it?
|
|
|
8 hours
|
|
10 hours
|
|
|
12 hours
|
|
24 hours
|
|
Answer: Option C
Explanation:
A's 1 hour's work =
|
1
|
;
|
4
|
(B + C)'s 1 hour's work =
|
1
|
;
|
3
|
(A + C)'s 1 hour's work =
|
1
|
.
|
2
|
(A + B + C)'s 1 hour's work =
|
|
1
|
+
|
1
|
|
=
|
7
|
.
|
4
|
3
|
12
|
B's 1 hour's work =
|
|
7
|
-
|
1
|
|
=
|
1
|
.
|
12
|
2
|
12
|
B alone will take 12 hours to do the work.
