Some persons can do a piece of work in 12 days. Two times the number of such persons will do half of that work in
Answer: D
Let x men can do the in 12 days and the required number of days be z
More men, Less days [Indirect Proportion]
Less work, Less days [Direct Proportion ]
men2x:xwork1:12 :: 12 : z
∴2x×1×z=x×12×12
⇒z=3