Problem:

Marcus Simmons caught the flu and needed to see the doctor. Simmons called to set up an appointment and was told to come in at 1:00 p.m.

Simmons arrived at the doctor's office promptly at 1:00 p.m. The waiting room had five other people in it. Patients were admitted from the waiting room in FIFO (first-in, first-out) order at a rate of 5 minutes per patient. After waiting until his turn, a nurse finally invited Simmons to an examining room. Once in there, Simmons waited another 5 minutes before a nurse arrived to take some basic readings (temperature, blood pressure). The nurse needed 10 minutes to collect this clinical information. After the nurse left, Simmons waited 30 additional minutes before the doctor arrived. The doctor diagnosed the flu and provided a prescription for antibiotics, which took 5 minutes. Before leaving the doctor's office, Simmons waited 10 minutes at the business office to pay for the visit.

Simmons spent 5 minutes walking next door to fill the prescription at the pharmacy. There were four people in front of Simmons, each person requiring 5 minutes to fill and purchase a prescription. Simmons arrived home 15 minutes after paying for his prescription.

I have to figure out what time Simmons arrives home, how much of the total elapsed time from 1:00 p.m. until when Simmons arrived home was non-value-added time, and what the value-added ratio is.

I really need an explanation of how to find out all the answers. I have a hard time understanding how to get the non-value-added time. Thank you.