The following data table represents the total cost of a monthly cell phone bill as a function of the number of minutes that the phone is used each month.
minutes 500 750 1,000 1,250 1,500
total monthly cost (in dollars) $62 $77 $92 $107 $122
choose the correct linear model that represents the total monthly cost as a function of time.
y = 0.06x + 500
y = 16x + 32
y = 62x + 16
y = 0.06x + 32

answer:

d. 0.06x + 32

step-by-step explanation:

it needs high-low method of cost to determine variable and fixed cost, and then find the cost function.

given,

highest activity = 1500 minutes

lowest activity = 500 minutes

higest cost = $122

lowest cost = $62

we know, variable cost under high-low method = (highest cost - lowest cost) / (highest activitiy - lowest activity)

therefore, variable cost = $(122 - 62)/(1500 - 500) minutes

variable cost = $60/1000 = $0.06

fixed cost = total cost in highest activity - variable cost per minute * highest activity

fixed cost = $122 - ($0.06*1500)

fixed cost = $122 - $90 = $32

therefore, liner cost function = variable cost per minute * fixed cost

y = 0.06x + $32

therefore, d is the answer.