y and x have a proportional relationship, and y = 15 when x = 3. What is the value of x when y = 4?Enter your answer in the box.y and x have a proportional relationship, and y = 12 when x = 5. What is the value of y when x = 8?Enter your answer in the box

Y and x have a proportional relationship, and y = 15 when x = 3. What is the value of x when y = 4?

y = kx
15 = 3k
k = 15/3
k = 5
so
What is the value of x when y = 4?
y = kx
4 = 5 * x
x = 4/5
x = 0.8

answer
x = 0.8 when y = 4
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y and x have a proportional relationship, and y = 12 when x = 5. What is the value of y when x = 8?

y = kx
12 = 5k
k = 12/5
k = 2.4

so
What is the value of y when x = 8?

y = kx
y = 2.4 * 8
y = 19.2

answer
y = 19.2  when x = 8