Item 16 The variables x and y vary directly. Use the values to find the constant of proportionality, k. Then write an equation that relates x and y. Item 16 The variables x and y vary directly. Use the values to find the constant of proportionality, k. Then write an equation that relates x and y.

k = 2

x = 2y

Step-by-step explanation:

If variables x and y vary directly, this is expressed as;

x ∝ y

x = ky

k is the proportionality constant

Let's assume the value of x and y since we are not given;

x = 20

y = 10

Substitute

20 = k(10)

10k = 20

k = 20/10

k = 2

Hence the constant of proportionality is 2

Substitute i=k = 2 into the equation x = ky

x = 2y

Hence an equation that relates x and y is x = 2y

Note that the values here are assumed value, you can use the same method for any values of x and y

36 girls

step-by-step explanation:

the 48 boys is 4 parts of the ratio

divide 48 by 4 to obtain one part of the ratio

= 12 ← 1 part of the ratio

3 parts = 3 × 12 = 36 ← number of girls