SOLUTION: AT&T offers a Smartphone plan that includes unlimited talk and text for $25 per month with an additional $15 charged for each GB of data used in the monthly billing cycle. Verizo

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Question 1092467: AT&T offers a Smartphone plan that includes unlimited talk and text for $25 per month with an additional $15 charged for each GB of data used in the monthly billing cycle.
Verizon Wireless offers a similar Smartphone plan that also includes unlimited talk and text for $40 per month with an additional $10 charged for each GB of data used in the monthly billing cycle.
How many GB of data would you have to use per month for Verizon’s
plan to be the better deal?
Answer by Theo(13342) About Me  (Show Source):
You can put this solution on YOUR website!
let x represent the number of gigbabytes used each month.

the at&t plan is 25 + 15 * x

the verizon plan is 40 + 10 * x

for the verizon plan to cost less than the at&t plan, then 40 + 10 * x must be less than 25 + 15 * x

your equation is 40 + 10 * x < 25 + 15 * x.

subtract 25 from both sides of the equation and subtract 10 * x from both sides of the equation to get 15 < 5 * x.

divide both sides of the equation by 5 to get 3 < x.

solve for x to get x > 3.

the verizon plan will cost less when the gigabytes of use each month is greater than 3.

look at 2, 3, and 4 gigabytes of usage per month.

the verizon plan will cost 60, 70, and 80 dollars per month.

the at&t plan will cost 55, 70, and 85 dollars per month.

at&t is less at 2, equal at 3 and more at 4.

any amount of use greater than 3 gigabytes of use will result in a smaller bill for verizon at these rates.