P can complete a piece of work in 18 days & B can do the same piece of work in 15 days. They started working together but after 3 days P left & Q alone completed the remaining work. The whole work was completed in how many days?	Select.
A) 12 days B) 12.5 days C) 13 days D) 14.5 days E) 15.5 days
Both together worked for 3 days.   In 3 days , P can do = 3 x   1   18   =   1   6   th work   In 3 days, Q can do = 3 x   1   15   =   1   5   th work   In 3 days , work finished =   1   6   +   1   5   =   11   30   12.5 daysalance work =   19   30   12.5 daysalance work finished by Q =&gt; Time taken by Q to finish the balance work =   19   30   x 15 = 9.5 days   The whole work was completed in  9.5 + 3= 
<gadget id="calculator"> 9.5 + 3</gadget>
<output>12.5</output>
12.5 days   12.5 days
<result>B</result>
P can complete a piece of work in 18 days & B can do the same piece of work in 15 days. They started working together but after 3 days P left & Q alone completed the remaining work. The whole work was completed in how many days?