Respuesta :

haneul
The answer is y = 12 when x = 30. You can prove this through some properties of mathematics. Multiply 6 by 2 if x = 30. 30 is two times 15, so it makes sense.
Hope that answered your question.

The problem does not specify whether it is a proportional variation or an inversely proportional variation, so both cases will be solved.

case a) proportional variation

we know that

A relationship between two variables, x, and y, represent a proportional variation if it can be expressed in the form

[tex] \frac{y}{x} =k [/tex]

Find the value of k

[tex] y=6\\ x=30\\ k=\frac{6}{30} =\frac{1}{5} [/tex]

Find the value of y for x=[tex] 15 [/tex]

[tex] y=kx\\ y=\frac{1}{5} *15\\ y=3 [/tex]

the answer case a) is

[tex] y=3 [/tex]

case b) inverse variation

we know that

A relationship between two variables, x, and y, represent an inverse variation if it can be expressed in the form

[tex] yx =k [/tex]

Find the value of k

[tex] y=6\\ x=30\\ k=30*6=180 [/tex]

Find the value of y for x=[tex] 15 [/tex]

[tex] yx=k\\ y=\frac{180}{15}\\ y=12 [/tex]

the answer case b) is

[tex] y=12 [/tex]