Question

Debra purchased a prepaid phone card for $30. Long distance calls cost 16 cents a minute using this card. Debra used her card only once to make a long
distance call. If the remaining credit on her card is $22.48, how many minutes did her call last?

Answer 1

The answer is 47 minutes.

You basically imagine this: Debra has a phone card for $30. She used x minutes every 16 cents. You end up with $22.48.

30 - (0.16x) = 22.48

You can basically graph that equation and the x-intercept will show you your answer. x = 47