A can do a piece of work in 6days, and B can do it in 5days. If C, who can do the work in 12days, joins them, how long will they take to complete the work?	Options
A) 2days	B) 3.5days	C) 2.2days	D) 4days	E) 5.7days
A,B, and 2.2days do the work in = 6*5*12/6*5+5*12+6*12 = 360/162= 2.2 days   Answer is 2.2days
<result>C</result>
A can do a piece of work in 6days, and B can do it in 5days. If C, who can do the work in 12days, joins them, how long will they take to complete the work?