I thought this would be simple, as I'm familiar with algebra and not really "The constant of proportionality," but I will do my best.
So this said "Constant of proportionality," is referring to basically the answers for the equation when X equals certain numbers.
Make a table of different answers when you plug in X and you get the 'Constant of proportionality.'
y = 2.5x + 3
y = 2.5(1) + 3
y = 2.5 + 3
y = 5.5
Since we plugged in 1 for X and got 5.5 for Y, our input and output is (1, 5.5)
Replace X for a different value, and you will get a bunch of different numbers that will in essence be your function inputs and outputs. Make a table of these and you have your answer.
EXAMPLE -
-= x =- -= y =-
-= 1 =- -= 5.5 =-
-= 2 =- -= 8 =-
-= 3 =- -= 11.5 =-
-= 4 =- -= 13 =-
So there you have it. I hope this helps! If you have any further questions, don't hesitate to ask.
Your proportion should look something like this

After cross multiplication, you should end up with this equation

After dividing 4 on both sides, you should get that x=9
Answer:
jelly=3.75
trail=2.75
Step-by-step explanation:
1) I put them in two separate brakets.
2) I solved it by equating both of them.
Answer:
i think it would be 30
Step-by-step explanation: