A cell phone company offers two different plans. Plan A costs $96 per month for unlimited talk and text. Plan B costs $0.20 per minute plus $0.10 per text message sent. You need to purchase a plan for your 14-year-old sister. Your sister currently uses 1,800 minutes and sends 1,650 texts each month. (1) What is your sister's total cost under each of the two plans? (2) Suppose your sister doubles her monthly usage to 3,600 minutes and sends 3,300 texts. What is your sister's total cost under each of the two plans?

1.

Plan A - Total Cost per month = $96

Plan B - Total Cost per month = $525

2.

Plan A - Total Cost per month = $96

Plan B - Total Cost per month = $1050

Explanation:

The total cost under Plan A is fixed. Thus it will not change whatever the number of texts and talk are for the month.

The total cost for Plan B is variable and will vary with change in number of talk and texts for the month. The total cost can be calculated by multiplying the cost per talk with the number of minutes per months plus the cost per text by the number of texts per month.

Plan A - Total Cost per month = $96

Plan B - Total Cost per month = 0.2 * talk minutes per month + 0.1 * texts per month

1.

Plan A - Total Cost per month = $96

Plan B - Total Cost per month = 0.2 * 1800 + 0.1 * 1650 = $525

2.

Plan A - Total Cost per month = $96

Plan B - Total Cost per month = 0.2 * 3600 + 0.1 * 3300 = $1050