A works twice as fast as B.If B can complete a work in 18 days independently,the number of days in which A and B can together finish the work is:  Options:
A) 4 days
B) 6 days
C) 8 days
D) 10 days
E) 12 days
Explanation:   Ratio of rates of working of A and B =2:1. So, ratio of times taken =1:2   A's 1 day's work=1/9   6 days's 1 day's work=1/18   (A+6 days)'s 1 day's work=(1/9 + 1/18)=3/18=1/6   so, A and 6 days together can finish the work in 6 days   ANSWER IS 6 days
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A works twice as fast as B.If B can complete a work in 18 days independently,the number of days in which A and B can together finish the work is: