Question

A company offers two plans for high speed internet service. With Plan A, you buy the modem and

pay a monthly fee for internet service. With plan B, the modem is free, but you pay a higher monthly
fee than for plan A.
Plan A: You pay $200 for the modem and $30 per month for service.
Plan B: The modem is free and you pay $40 per month for service.
Question 1: After how many months are the total costs of the plans the same?
Question 2: When is Plan A a better deal? Explain your answer.

Answer 1

1. 20 months

2. Plan A is better deal. After 20 month, the total monthly cost of plan A ($30/month) is less than plan B ($40/month)

Explanation:

y = total cost per number of months

m = modem

x = cost

n = number of months

Plan A: y = m + xn = 200 + 30n

Plan B: y = m +xn = 0 + 40n

Q1. if total cost is the same : 200 + 30n = 40n >>> 10n = 200 >>> n = 20

Q2. After 20 month, the total monthly cost of plan A is less than plan B

Plan A = $30/month

Plan B = $40/month

Answer 2

Explanation:

1.Let x be months

200+30x=40x

10x=200

x=20

After 20months are the total costs of the plans the same.

2.when in the 21st month and after it, PlanA is a better deal, because only need to pay $30per month.（PlanB need to pay $40per month）