RS would be equal to 25 because 15 + 25 = 40
Good day ~_~ /////////////
600/100 as a mixed number would be 6
The total number of cookies baked by grandma = 96
Number of grandchildren = 8
As given, all cookies were evenly divided among 8 children, let us assume that everyone except Cindy got equal share. So on being divided equally, it becomes, 
cookies per children.
But, as mentioned that Cindy received 'c' cookies less, so let us suppose Cindy received 'x' cookies.
Expression becomes: 
Hence, Cindy received 12-c cookies.
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.
