I have added visual representaion for you to see and color coded the carpets. Hope this helps!!!!
1: 10 quarters
2: 20 dimes
3: a dollar and 5 dimes
4: a dollar and 2 quarters
5: 6 quarters and 15dimes
A
to calculate the slope m use the gradient formula
m = ( y₂ - y₁ ) / (x₂ - x₁ )
with (x₁, y₁ ) = (7, - 2 ) and (x₂, y₂ ) = (- 1, - 5 )
m = 
= 
= 
→ A
Ok,so you can represent the students as K and Y as the cookies eaten.X is your constant of proportionality (the number you multiply to k to get y).
For the first one,14/2 which equals 7.Try the next set,21/3=7 also and finally 35/5=7.You can see that the C.O.P is 7.
