How much credit will be available math problem?

Suppose that the credit remaining on a phone card (in dollars) is a linear function of the total calling time (in minutes). When graphed, the function gives a line with a slope of -0.16 . See the figure below.





There is $30.92 in credit remaining on the card after 37 minutes of calls. How much credit will there be after 52 minutes of calls?|||if you have a slope of -.16, that means that for every minute, you lose 16 cents on your credit.


52-37=15


so in 15 min you will lose 15*.16 = $2.40


So $30.92-$2.40 = $28.52