A gym charges a $615 yearly fee for membership plus $50 for each hour of personal training. What is the average total cost per hour of training if a member works with a personal trainer for 30 hours in a year? Do not include the dollar sign ($) in your answer.

The average total cost per hour of training is $70.5

Step-by-step explanation:

The form of the linear function is f (x) = m x + b, where

m is the average rate b is the initial value

∵ The gym charges a $615 yearly fee for membership plus

$50 for each hour of personal training

- That means the initial amount is 615 and the average rate is 50

∴ m = 50 dollars per hour

∴ b = 615 ⇒ fixed fee

- Substitute m and b in the form of the linear function

∴ c (x) = 50 x + 615, where c (x) is the cost per year for x

training hours

∵ A member works with a personal trainer for 30 hours in a year

- That means x = 30

∴ x = 30

- Find the total cost of this year by substituting x by 30

∴ c (30) = 50 (30) + 615

∴ c (30) = 1500 + 615

∴ c (30) = 2115

∴ The total cost of this year is $2115

To find the average cost per hour divide the total cost by the number of the training hours

∵ Average cost per hour = 2115 : 30

∴ The average cost per hour = 70.5 dollars

∴ The average total cost per hour of training is $70.5