Question

Sal is trying to determine which cell phone and service plan to buy for his mother. The first phone costs $100 and $55 per month for unlimited usage. The second phone costs $150 and $51 per month. The inequality that will determine the number of months (x) for the cost of the second phone to be less than the cost of the first phone is:

a) (150 + 51x < 100 + 55x)
b) (100 + 55x < 150 + 51x)
c) (150x + 51 < 100x + 55)
d) (100x + 55 < 150x + 51)

Answer 1

The inequality that will determine the number of months (x) for the cost of the second phone to be less than the cost of the first phone is (150 + 51x < 100 + 55x).

Step-by-step explanation:

The inequality that will determine the number of months (x) for the cost of the second phone to be less than the cost of the first phone is: (150 + 51x < 100 + 55x).

To solve this inequality, we need to isolate the x variable. Start by subtracting 51x from both sides of the inequality to get: 150 < 100 + 4x. Then, subtract 100 from both sides to get: 50 < 4x. Finally, divide both sides by 4 to solve for x: 12.5 < x. This means that in order for the cost of the second phone to be less than the cost of the first phone, Sal will need to use the second phone for more than 12.5 months.