Question

John's phone company offers 2 cell phone plans, A and B. Both plans offer 450 free minutes per month, but plan A charges $40 per month and $0.35 for each additional minute, while plan B charges $45 per month and $0.30 for each additional minute. Which inequality shows the number of minutes, x, that John may use in a month in order to make plan B the better plan for that month?

A.
40 + 0.35(x − 450) 45 + 0.30(x − 450)

D.
40 + 0.35x > 45 + 0.30x

Answer 1

The inequality which shows the number of minutes, x, that John use in a month in order to make plan B the better plan for that month is 40 + 0.35(x - 450) > 45 + 0.30(x - 450).

How to write inequality?

let

x = number of minutes

Plan A:

40 + 0.35(x - 450)

Plan B:

45 + 0.30(x - 450)

The inequality which shows plan A is more expensive than plan B

40 + 0.35(x - 450) > 45 + 0.30(x - 450)

Ut can also be written as

45 + 0.30(x - 450) < 40 + 0.35(x - 450)

Answer 2

Answer: 45 + 0.30(x-450) > 40 + 0.35(x-450)

Explanation:

Given: Free minutes = 450

For plan A,

Fix charge = $40

Charge per minute after free minutes = $0.35

For plan B,

Fix charge = $45

Charge per minute after free minutes = $0.30

Let x be the additional minutes.

Charges according to plan A = 40 + 0.35(x-450)

Charges according to plan B = 45 + 0.30(x-450)

If plan B is better than plan A.

45 + 0.30(x-450) > 40 + 0.35(x-450)

Required inequality : 45 + 0.30(x-450) > 40 + 0.35(x-450)