Question 1038207
Paul can do a certain job in half the time that Jim requires to do it.


 Jim worked alone for an hour and stopped; then Paul completed the job in 10 hours. What length of time, in hours, would Paul, working alone, take to do the whole job?

Let jim take x hours to do the job

So he does 1/x of the job in 1 hour

Paul takes x/2 hours to do the job

so he does 2/x of the job in 1 hour

After jim worked for 1 hour balance job was 

(1-1/x) = (x-1)/x 

Paul does 2/x of the job in 1 hour

so he takes ((x-1)/x)/(2/x) hours to do the remaing job 

((x-1)/x)/(2/x) = 10

(x-1)/x =5x

x-1=5
x= 4 No of hours Jim takes to complete the job

Paul will take 2 hours