Answer:
The platinum plan should be selected.
Explanation:
This can be determined using the following 4 steps:
Step 1: Calculation of the total expected minutes in a month
Total number of expected minutes in a month = Number of hours Miller is expected to use her phone per month * Numbe of minutes in one hour = 21 hour * 60 minutes = 1,260 minute
Step 2: Calculation of the expected cost of regular plan
Expected fixed cost of 1,000 minutes per months = $55
Expected cost of minutes over 1,000 minutes = (Total number of expected minutes in a month - 1,000 minutes) * Cost per minute = (1,260 - 1,000) * $0.33 = 260 * $0.33 = $85.80
Expected cost of regular plan = Expected fixed cost of 1,000 minutes per months + Expected cost of minutes over 1,000 minutes = $55 + $85.80 = $140.80
Step 3: Calculation of the expected cost of platinum plan
Expected fixed cost of 1,200 minutes per months = $100
Expected cost of minutes over 1,200 minutes = (Total number of expected minutes in a month - 1,200 minutes) * Cost per minute = (1,260 - 1,200) * $0.25 = 60 * $0.25 = $15
Expected cost of platinum plan = Expected fixed cost of 1,200 minutes per months + Expected cost of minutes over 1,200 minutes = $100 + $15 = $115
Step 4: Decision
Expected cost of regular plan = $140.80
Expected cost of platinum plan = $115
Since the expected cost of platinum plan of $115 is lower than the expected cost of regular plan of $140.80, the platinum plan should be selected.
