Answer: 16
Explanation:
The constant of proportionality is a ratio that exist between two directly proportional quantities. From the question, recipe says to use 1.5 cups of flour to make 24 cookies.
y = the number of cookies made
x = the number of cups of flour used
y = kx
k = y/x
k = 24/1.5
k = 16
Therefore, the constant of proportionality which relates the number of cookies made, y, to number of cups of flour used, x is 16.