Answer: $4.50
Step-by-step explanation: So, to start off you would need to multiply the amount of folders by the amount that they cost (which is $0.75)
You would get $10.50 as the total amount she paid for the 14 folders.
Finally you subtract the $15 dollars from $10.50, here you would get the answer of $4.40 as her change.
If you think this is wrong then feel free to tell me and I can retry. :)
