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? Choose the correct answer.
A) 12	B) 11	C) 10	D) 9	E) 8
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 = 17X ( Assume)   B’s work alone for 23 days = 23 x 9 = 207   So, the work done by A and B together = (360 - 207)= 
<gadget id="calculator">(360 - 207)</gadget>
<output>153</output>
153 units   Therefore, 17X= 153   =&gt; 9 units   Therefore, the number of days after which A left the work was 9 days.   ANSWER:9
<result>D</result>
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?