An Amazon packaging plant can ship 315 packages in 7 hours. What is the constant of proportionality that relates the number of packages shipped, y, to the number of hours, x?

constant of proportionality is 45 packages an hour.

Step-by-step explanation:

you do 315 divided by 7. the x is hours and the y is packages.

step-by-step explanation:

the ratio of red paint to blue paint is always 9/7. that means that, whatever x's value, (4x+12)/(4x-4) has that same ratio. so, set up an equation and cross-multiply to solve for x:

9/7 = (4x+12)/(4x-4)

9(4x-4) = 7(4x+12)

36x - 36 = 28x + 84

8x - 36 = 84

8x = 120

x = 15