Martina purchased a prepaid phone card for $20. long distance calls cost 24 cents a minute using this card. martina used her card once to make a long distance call. if the remaining credit on her card is $13.28, how many minutes did her call last?

Delbert keeps track of total of the total number of points he earns on homework assignments, each of which is worth 60 points. at the end of the semester he has 810 points. write an equation for delbert’s average homework score a in terms of the number of assignments n.