Answer :
"The variable y varies directly as x."
For this type of condition, we can just interpret this as getting the missing value through ratios and proportions.
We get,
[tex]\text{ 20 : 12 = 15 : y}[/tex][tex]\text{ 20 : 12 = 15 : y }\rightarrow\text{ }\frac{\text{ 20}}{\text{ 12}}\text{ = }\frac{\text{ 15}}{\text{ y}}[/tex][tex]\text{ (20)(y) = (15)(12)}[/tex][tex]\text{ 20y = 180}[/tex][tex]\text{ }\frac{\text{20y}}{20}\text{ = }\frac{\text{180}}{20}[/tex][tex]\text{ y = 9}[/tex]Therefore, at x = 15, y = 9.
The answer is letter B.