Question

Martina purchased a prepaid phone card for $20. Long distance calls cost 22 cents a minute

using this card. Martina used her card only once to make a long distance call.
If the remaining credit on her card is $9.66, how many minutes did her call last?

Answer 1

47.

Explanation:

1) Martina spent 20-9.66=10.34 [USD];

2) the required time can be calculated as

10.34/0.22=47 [minutes].