Time spent by employee = 2 hours = 120 minutes
Time spent by machine = 30 minutes
Ratio:
[tex] = \frac{120}{30 } [/tex]
[tex] = \frac{12}{3} [/tex]
[tex] = \frac{4}{1 } [/tex]
= 4 : 1
Difference between the time taken by a employee and machine to do a job
= 120 - 30
= 90 minutes