Frances can complete a job in 16 hours, and Joan can complete the same job in 8 hours. Frances starts the job at 9 a.m., and stops working at 3 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:
A) 9 p.m.
B) 7 p.m.
C) 8 p.m.
D) 10 p.m.
E) 12 p.m.
Let the total work be 24 units.   Frances can complete 1.5 units/hr   Joan can complete 3 units/hr   Work done by Frances in 6 hours is 9 units ; work left for Joan is 15 units ( 24 - 9)   Time required by Jones to complete the remaining work will be   15/3= 
<gadget id="calculator">  15/3</gadget>
<output>5</output>
&gt; 5 hours   Given Jones starts at 4PM , so she would complete the work at 9 PM   9 p.m.nswer will be (9 p.m.)
<result>A</result>
Frances can complete a job in 16 hours, and Joan can complete the same job in 8 hours. Frances starts the job at 9 a.m., and stops working at 3 p.m. If Joan starts working at 4 p.m. to complete the job, at what time is the job finished?