127. A can do a certain work in the same time in which B and C together can do it. If A and B together could do it in 10 days and C alone in 50 days, then B alone could do it in:

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

10

C’s 1 day’s work =
1

50

(A + B + C)’s 1 day’s work =

1
+
1

=
6
=
3
. …. (i)

10
50
50
25

A’s 1 day’s work = (B + C)’s 1 day’s work …. (ii)

From (i) and (ii), we get: 2 x (A’s 1 day’s work) =
3

25

A’s 1 day’s work =
3
.

50

B’s 1 day’s work

1
–
3

=
2
=
1
.

10
50
50
25

So, B alone could do the work in 25 days.