Mixed Costs and Cost Formula

Callie's Gym is a complete fitness center. Owner Callie Ducain employs various fitness trainers who are expected to staff the front desk and to teach fitness classes. While on the front desk, trainers answer the phone, handle walk$-$ins and show them around the gym, answer member questions about the weight machines, and do light cleaning $($wiping down the equipment, vacuuming the floor$).$ The trainers also teach fitness classes $($e$.$g$.,$ pilates, spinning, body pump$)$ according to their own interest and training level. The cost of the fitness trainers is $$600$ per month and $$20$ per class taught. Last month, $100$ classes were taught.

Required:

$1.$ Develop a cost equation for total cost of labor.

Total labor cost $=$ $fill in the blank $1$

$+$ $fill in the blank $2$

per class taught

$2.$ What was total variable labor cost last month?

$fill in the blank $3$

$3.$ What was total labor cost last month?

$fill in the blank $4$

$4.$ What was the unit cost of labor $($per class$)$ for last month?

$fill in the blank $5$

per class

$5.$ What if Callie increased the number of classes offered by $50$ percent?

a$.$ What would be the total labor cost?

$fill in the blank $6$

b$.$ The unit labor cost?

$fill in the blank $7$

c$.$ Explain why the unit labor cost decreased.