A works twice as fast as B. If B can complete a work in 12 days independently, the number of days in which A and B can together finish the work in :
Choose one:
A) 4 days	B) 6 days	C) 8 days	D) 18 days	E) 28 days
Explanation:   Ratio of rates of working of A and B = 2 : 1.   So, ratio of times taken = 1 : 2.   B's 1 day's work =1/12   A's 1 day's work =	1/6 ; (2 times of B's work)   (A + B)'s 1 day's work = (1/6 +1/12)=3/12=1/4   So, A and B together can finish the work in 4 days.   4 daysNSWER IS 4 days
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A works twice as fast as B. If B can complete a work in 12 days independently, the number of days in which A and B can together finish the work in :