If 50 apprentices can finish a job in 4 hours, and 30 journeymen can finish the same job in 7 hours, how much of the job should be completed by 10 apprentices and 15 journeymen in one hour?
Choose the most appropriate option.
A) 17/140  B) 29/180  C) 26/143  D) 1/5  E) 39/121
50 apprentices can finish the job in 4 hours,thus:   10 apprentices can finish the job in   4*5= 
<gadget id="calculator">  4*5</gadget>
<output>20</output>
20 hours;   In 1 hour 10 apprentices can finish 1/20 of the job.   30 journeymen can finish the same job in 4,5 hours,thus:   15 journeymen can finish the job in  7*2= 
<gadget id="calculator"> 7*2</gadget>
<output>14</output>
14 hours;   In 1 hour 15 journeymen can finish 1/14 of the job.   Therefore, in 1 hour 10 apprentices and 15 journeymen can finish 1/20+1/14=17/140 of the job.   17/140nswer: 17/140
<result>A</result>
If 50 apprentices can finish a job in 4 hours, and 30 journeymen can finish the same job in 7 hours, how much of the job should be completed by 10 apprentices and 15 journeymen in one hour?