117. A and B can complete a work in 15 days and 10 days respectively. They started doing the work together but after 2 days B had to leave and A alone completed the remaining work. The whole work was completed in :

✅ The correct answer is option C.
(A + B)’s 1 day’s work =

1
+
1

=
1
.

15
10
6

Work done by A and B in 2 days =

1
x 2

=
1
.

6
3

Remaining work =

1 –
1

=
2
.

3
3

Now,
1
work is done by A in 1 day.

15

2
work will be done by a in

15 x
2

= 10 days.

3
3

Hence, the total time taken = (10 + 2) = 12 days.