Answer:
She has 7.75 left on her card
Explanation:
She starts with $15.25 on the card. The formula is N = 15.25 - 0.25x.
She bought 30 of the film. Replace x with 30.
N = 15.25 - 0.25(30)
Multiply 0.25 by 30. (you can think of this as 1/4 of 30)
N = 15.25 - 7.50
Subtract the two remaining numbers
N = 7.75