Question #86faf

1 Answer
Sep 8, 2017

158158 minutes

Explanation:

Carlos pays a monthly fee of $6$6. In a mathematical function, this would be represented by a constant of 66.

He also pays 88 cents, or $0.08$0.08, per minute spoken. If xx were the number of minutes spoken, this would be represented by 0.08 x0.08x.

Overall, Carlos' long distance bill can be represented by the function:

f(x) = 0.08 x + 6f(x)=0.08x+6; where f(x)f(x) is the long distance bill, and xx is the number of minutes spoken.

Last month, his long distance bill was $18.64$18.64.

Let's replace f(x)f(x) with 18.6418.64:

Rightarrow 18.64 = 0.08 x + 618.64=0.08x+6

If we solve for xx, we will find the number of minutes for which Carlos was billed:

Rightarrow 12.64 = 0.08 x12.64=0.08x

Rightarrow 158 = x158=x

therefore x = 158

Therefore, Carlos was billed for 158 minutes.