If A and B can do a piece of work in 7.5 days. If B works 1/2 of work and remaining work was completed by A, taking total time of 20 days to complete the work. If b is more efficient then B can do work in how many days?
Choose the correct choice from the following answers.
A) 9 days  B) 10 days  C) 11 days  D) 12 days  E) 13 days
1/A + 1/B = 2/15 or (A+B)/AB= 2/15 ----(i)   (1/2)/(1/A) + (1/2)/(1/B) = 20 or A/2 + B/2 = 20 or A+B= 40 ----(ii)   Substituting A+B= 40 from (ii) in (i), we get AB= 300   Now finding the factors of 300, whose sum is 40, we have 10 and 30   As B is more efficient than A, B can do the work in 10 days.   ANSWER:10 days
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If A and B can do a piece of work in 7.5 days. If B works 1/2 of work and remaining work was completed by A, taking total time of 20 days to complete the work. If b is more efficient then B can do work in how many days?