Question

Unit 4 Lesson 9 Cumulative Practice Problems 1. Cell phone Plan A costs $70 per month and comes with a free $500 phone. Cell phone Plan B costs $50 per month but does not come with a phone. If you buy the $500 phone and choose Plan B, how many months is it until your cost is the same as Plan A's? ​

Answer 1

To find out how many months it will take for the cost of Plan B to equal Plan A, subtract the cost of the phone from the monthly cost of Plan A and calculate the difference in the monthly costs with Plan B. Divide the initial cost of the phone by the monthly cost difference to determine the number of months until the costs are equal.

Step-by-step explanation:

To find out how many months it will take until the cost of Plan B is the same as Plan A, we need to consider the initial cost of the phone and the monthly costs of the two plans.

First, we subtract the cost of the phone ($500) from the monthly cost of Plan A ($70) to get the effective monthly cost of Plan A, which is $70 - $500 = $20.

Next, we calculate the difference in the monthly costs of the two plans: $20 (Plan A) - $50 (Plan B) = -$30.

Finally, we divide the initial cost of the phone ($500) by the difference in the monthly costs (-$30) to find out how many months it will take for Plan B to become cost-effective: $500 / -$30 = -16.67 months.

Since we can't have a negative number of months, we round up to the nearest whole number, which gives us 17 months.