If y varies directly as x and x = 9 when y = 15 , find y when x = 33

This would practically be very reliable of course. We can see in the sentence above that y and x, and x and y are both depending on each other. So, now that this has been considered, we can see that whenever "x" would be a certain number, this would show you that "y" would also be a certain number, and depending how much "x" or "y" would move, it would also change these variable no matter how they move.

This would be a matter of division. As we can see above on how 9 and 15 could be divisible down the line as they multiply.

Therefore, we would then see how many times would "x" which is 9, how many times that would go in 33.

Let's start!



We take this "3.6" away from this, and we would plug it into "y".

We then do the following:



Therefore, when "x" = 33, "y" would then equal 55.

Your  

Need to find the ratio:

y = kx

15 = k9

k = 15/9

now find y when x = 33

y = (15/9)33

y = 55