joe and Eric have to ship 75 packages. Joe can do the job alone in 5 hours. if Eric helps, they get it done in 4 hours. How long would it take Eric to do the job alone?​

Respuesta :

Eric took 20 hours to do the job alone.

Step-by-step explanation:

Given :

  • Total work = 75 packages
  • Joe took 5 hours to complete the total work.

The amount of work Joe alone can do per hour = 75/5 = 15 packages.

The amount of work Joe and Eric together do per hour = 75/4 = 18.75

The amount of work Eric alone can do per hour = 18.75 - 15 = 3.75

The time Eric took to complete the entire work = 75 / 3.75 = 20 hours.