2/8 or 1/4. 1/4 is just simplified. I hope it helps!
It seems to me, that if you were to add the price of all three items together, then multiply by 7.5%, you'd have the answer. Remember that 7.5% = .075 ... in other words, that is the number you would multiply the sum of the items by. Does that help?
You can set up an equation based off of the information given:
x represents the unknown number
3/5x - 1 = 23
add 1 to both sides to isolate the 3/5x
3/5x = 24
divide both sides by 3/5 to solve for x
x = 120/3
120/3 can be simplified into 40
Final answer: x = 40
It could sometimes be proportional. The reasoning here is that if all the items have different prices it won't be, however if the items you are ordering all have the same price they will be!