Question

a smart phone plan has a monthly base fee that includes 5 gigabytes of data. an overage charge is applied when the data usage exceed 5 gigabytes. the equation $c = 59 + 15(g - 5)$ models the plan, where $c$ represents the monthly cost, in dollars, and $g$ represents the total number of gigabytes used for the month. what does the value 15 represent in the equation?
a the base fee per month, in dollars, for the plan.
b the cost, in dollars, for each additional gigabyte used.
c the average cost, in dollars, for data usage per month.
d the average data usage, in gigabytes, per month.

Explanation:

The equation $C = 59 + 15(g - 5)$ is a linear cost model. The term $(g - 5)$ calculates the number of gigabytes used beyond the included 5 GB. The coefficient 15 multiplies this overage amount, so it represents the cost per additional gigabyte. The base fee is the constant 59, so option A is incorrect. Options C and D do not align with the role of 15 in the cost equation.

Answer:

B. The cost, in dollars, for each additional gigabyte used.