Answer:
33 minutes.
Explanation:
We have been given that Martina purchased a prepaid phone card for $15 . Long distance calls cost 22 cents a minute using this card. Martina used her card only once to make a long distance call and the remaining credit on her card is $7.74.
Let us find the amount spent on the long spent call by subtracting $7.74 from $15.


Therefore, Martina spent $7.26 on long distance call.
As each minute of long distance call costs 22 cents ($0.22), so to find the number of minutes of Martina's call we will divide 7.26 by 0.22.


Therefore, Martina's long distance call last for 33 minutes.