Write a equation using function notation that describes the situation

Question

You have a prepaid telephone (c) with 24 dollars left on it. Each call (n) cost $1.5 per minute.

Answer 1

They appear to be defining (c) as the current amount left on your prepaid plan, and (n) is the number of calls.

The amount left is going to be the amount at the beginning ($24) minus the number of minutes you've called (n) x the call rate $1.5 per minute. Put it all together and you get:

C = 24 - 1.5 * n.

In English, that's amount left on the card (c) is equal to $24 minus $1.5 times the number of minutes you've called (n).