116. A is 30% more efficient than B. How much time will they, working together, take to complete a job which A alone could have done in 23 days?

✅ The correct answer is option B.
Ratio of times taken by A and B = 100 : 130 = 10 : 13.
Suppose B takes x days to do the work.

Then, 10 : 13 :: 23 : x         x =

23 x 13

        x =
299
.

10
10

A’s 1 day’s work =
1
;

23

B’s 1 day’s work =
10
.

299

(A + B)’s 1 day’s work =

1
+
10

=
23
=
1
.

23
299
299
13

Therefore, A and B together can complete the work in 13 days.