Frances can complete a job in 6 hours, and Joan can complete the same job in 12 hours. Frances starts the job at 9 a.m., and stops working at 1 p.m. If Joan starts working at 4 p.m. to complete the job, at what time is the job finished?  Choose the correct choice from the following answers:
A) 6 p.m.  B) 7 p.m.  C) 12 p.m.  D) 10 p.m.  E) 8 p.m.
Let the total work be 24 units.   Frances can complete 4 units/hr   Joan can complete 2 units/hr   Work done by Frances in 4 hours is 16 units ; work left for Joan is 8 units ( 24 - 16)   Time required by Jones to complete the remaining work will be   8/2= 
<gadget id="calculator">  8/2</gadget>
<output>4</output>
&gt; 4 hours   Given Jones starts at 4 PM , so she would complete the work at 8 PM   Answer will be (8 p.m.)
<result>E</result>
Frances can complete a job in 6 hours, and Joan can complete the same job in 12 hours. Frances starts the job at 9 a.m., and stops working at 1 p.m. If Joan starts working at 4 p.m. to complete the job, at what time is the job finished?