SOLUTION: A clerk can add 40 columns of figures an hour by using an adding machine and 20 columns of figures an hour without using an adding machine. The total of number of hours it would ta

Question 250328: A clerk can add 40 columns of figures an hour by using an adding machine and 20 columns of figures an hour without using an adding machine. The total of number of hours it would take him to add 200 columns if he does 3/5 of the work by machine and the rest without the machine is?
Answer by ankor@dixie-net.com(22740) (Show Source): You can put this solution on YOUR website!
A clerk can add 40 columns of figures an hour by using an adding machine and 20 columns of figures an hour without using an adding machine.
The total of number of hours it would take him to add 200 columns if he does 3/5 of the work by machine and the rest without the machine is?
:
Time required to add 200 columns with machine: 200/40 = 5 hrs
Time required to add 200 columns without machine: 200/20 = 10 hrs
:
With Machine: *5 = 3 hrs to do 3/5 of the work
then
W/out Machine:*10 = 4 hrs to do remaining 2/5 of the work
:
Total time = 7 hrs
;
:
Is this true?
Machine does 3*40 = 120 columns
No machine does 4 * 20 = 80 columns
total done = 200 columns

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