Answer:
90 dollars
Explanation:
Hey there! We know that:
-the 40 dollar fee does not change no matter how much you use the phone
-10 cents for every minute of cell phone usage
Using this information, we can craft an equation to calculate how many dollars her cell phone bill will be with x amount of minutes she used her phone.
We can let y= amount in dollars of her bill, and x=amount of minutes she has used her phone, because the 40 dollar fee is not dependent on how often you use your phone.
Using that information, we get y=0.10x+40
We also know that she has used it for 500 minutes. Insert this amount into the variable x and we can solve it.
y=0.10(500)+40
=50+40
=90
Therefore, her bill is 90 dollars with her 500 minutes of usage.