Three pipes A, B and C can fill a tank in 6 hours. After working at it together for 2 hours, C is closed and A and B can fill the remaining part in 7 hours. The number of hours taken by C alone to fill the tank is:
[A].
10
[B].
12
[C].
14
[D].
16
Answer: Option D
Explanation:
Part filled in 2 hours =
2
=
1
6
3
Remaining part =
1 -
1
=
2
.
3
3
(A + B)'s 7 hour's work =
2
3
(A + B)'s 1 hour's work =
2
21
C's 1 hour's work = { (A + B + C)'s 1 hour's work } - { (A + B)'s 1 hour's work }
(A + B)'s 7 hour's work =