Machine A takes 100 hours to complete a certain job and starts that job at 7AM. After two hour of working alone, machine A is joined by machine B and together they complete the job at 6PM. How long would it have taken machine B to complete the jobif it had worked alone for the entire job?  Choose the correct choice from the following choices
A) 10.11
B) 9.99
C) 11.1
D) 44.11
E) 1.01
Let us assume total job = 100 units   A finishes 100 units in 100 hrs(given)   Hence A (working rate)= 1 units /hr   Now Given that A works for 2 hr( so 2 units done) then A and B finish total work in 15 hours. Hence A and B finish 98 units in 9 hours. Of these 1x9=9 units were done by A. Hence B did 89units in 9 hours.   Hence B(working rate)= 89/9 units /hr   Hence B takes 100x9/89 = 10.11 hours to complete the job.   10.11nswer 10.11.
<result>A</result>
Machine A takes 100 hours to complete a certain job and starts that job at 7AM. After two hour of working alone, machine A is joined by machine B and together they complete the job at 6PM. How long would it have taken machine B to complete the jobif it had worked alone for the entire job?