Liner functions help!

Question

Hey I need help for a homework question I don't quite understand it and my teacher didn't explain it to a point where I get it

Thanks!

 

Question: Lasean’s cell phone costs $30 per month plus additional fees. Text messaging is $0.10 per message, data usage is $5.00 per gigabyte, and phone calls are $0.05 per minute. Formulate an equation that can be used to determine Lasean’s monthly bill. Then solve the equation to determine Lasean’s bill for March if he sent 90 text messages, used 2 gigabytes of data, and talked for 45 minutes

Answer 1

Let's set up a linear equation first.

Let C be the total cost for the month

Let M be the base monthly cost ($30)

Let T be the number of text messages, each message with a cost of 10 cents or $0.10

Let G be the gigabyte usage which costs $5 per gigabyte

Finally, let P be the number of phone calls which are 5 cents, $0.05 each minute

 

So our equation would be

C = M + 0.10T + 5G + 0.05P

 

 

Now we need the cost for March with 90 text messages, 2 gigabytes of data and 45 minutes of phone calls.

C = 30 + 0.10(90) + 5(2) + 0.05(45)

C = 30 + 9 + 10 + 2.25

C = $51.25 The total cost for the month of March.