A and B can do a piece of work in 45 days and 40 days respectively. They began to do the work together but A leaves after some days and then B completed the remaining work in 23 days. The number of days after which A left the work was?
Answers
A) 12
B) 11
C) 10
D) 9
E) 8

Rationale: let the total units of work to be done be 360 . the units of work done by a in a single day = 8 similarly , the units of work done by b in a single day = 9 . a and b ’ s one day work = 17 units a and b worked together for some days = 17 x ( assume ) b ’ s work alone for 23 days = 23 x 9 = 207 so , the work done by a and b together = ( 360 - 207 ) = 153 units therefore , 17 x = 153 = > 9 units therefore , the number of days after which a left the work was 9 days . answer : d
Answer: D