The credit remaining on a phone card (in dollars) is a

Last updated: 7/12/2022

The credit remaining on a phone card (in dollars) is a linear function of the total calling time made with the card (in minutes). The remaining credit after 45 minutes of calls is $23.25, and the remaining credit after 72 minutes of calls is $19.20. What is the remaining credit after 79 minutes of calls?