Question

The variables y and x have a proportional relationship, and y=9 when x=2. What is the value of y when x=3?

Answer 1

For this case we have that by definition, if the variables "y" and "x" have a proportional relation, and$y = 9$when $x = 2$, then:

$\frac {x} {y} = \frac {2} {9}$

Now, we want to know the value of the variable "y" when $x = 3$, then:

$\frac {3} {y} = \frac {2} {9}$

Clearing "y" we have:

We multiply by "y" on both sides of the equation:

$y * \frac {3} {y} = y * \frac {2} {9}\\3 = \frac {2y} {9}$

We multiply by 9 on both sides:

$9 * 3 = \frac {2y} {9} * 9\\27 = 2y$

We divide by 2 on both sides:

$\frac {27} {2} = \frac {2y} {2}\\y = 13.5$

So, when $x = 3$then$y = 13.5$

Answer:

$y = 13.5$

Answer 2

I believe it should be 3