To average a set of numbers, add the numbers together and divide the total by the number of numbers that were added together. Below are a couple of practical examples to illustrate this procedure.
1. A water treatment facility feeds an alum dosage of 45 mg/l on Sunday, Monday, and Tuesday and feeds an alum dosage of 75 mg/l on Wednesday, Thursday, Friday, and Saturday. What was the water treatment facility's average daily alum dosage for the week?
Answer: 45 + 45 + 45 + 75 + 75 + 75 + 75 = 435 divided by 7 = 62 mg/l (rounded off)
2. A water treatment plant has six filters. At the end of the day, the filter hours on these filters are 14.5, 59.0, 71.5, 2.0, 88.5, and 33.0 hours. What is the filter-hour average for these filters?
Answer: 14.5 + 59.0 + 71.5 + 2.0 + 88.5 + 33.0 = 268.5 divided by 6 = 44.75 hours