Trey has a peanut allergy, so he eats granola bars that are nut free. A box of nut-free granola bars costs $4.50 after a 10% discount. Trey wants to know the regular price of the granola bars.

The regular price of the granola bars were $5 each.

Step-by-step explanation:

Hi, to answer this question we have to write an equation with the information given:

So, the original price of the granola bar (x) multiplied by 0.9 ( since 100% is the full price,1- 0.1= 0.9) equals to 4.50 (cost after discount)

Mathematically speaking

x (1- 0.1) = 4.50

x 0.9 =4.50

x = 4.50/0.9

x= 5

Feel free to ask for more if needed or if you did not understand something.