18..A, B and C can do a piece of work in 20, 30 and 60 days respectively. In how many days can A do the work if he is assisted by B and C on every third day?
A. 12 days
B. 15 days
C. 16 days
D. 18 days
Answer:
Option : B
A's 2 day's work =
|
|
1
|
x 2
|
|
=
|
1
|
20
|
10
|
(A + B + C)'s 1 day's work =
|
|
1
|
+
|
1
|
+
|
1
|
|
=
|
6
|
=
|
1
|
20
|
30
|
60
|
60
|
10
|
Work done in 3 days =
|
|
1
|
+
|
1
|
|
=
|
1
|
10
|
10
|
5
|
Now,
|
1
|
work is done in 3 days.
|
5
|
∴ Whole work will be done in (3 x 5) = 15 days.
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