Quiz on Work Done

Answer: Option B

Explanation:

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.