70.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:
A. 15 days
B. 20 days
C. 25 days
D. 30 days
Answer:
Option : C
(A + B)'s 1 day's work =
|
1
|
10
|
(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
|
