Donna purchased a prepaid phone card for $25. long distance calls cost 18 cents a minute using this card. donna used her card only once to make a long distance call. if the remaining credit on her card is $20.14, how many minutes did her call last?

First you figure out how much money she used so $25 - $20.14 which is equal to $5.86. Now you need to figure out how much minutes that is equal to $5.86. So you need to figure out what x is equal to in:  x *  ¢18 = $5.86.
x is equal to 32.555555 

so she was calling for 32.555555... minutes or if you are rounding it would be 32.6 minutes

hope this helps ^^