Question

the variable y varies directly as x. when x =20, y= 12 what is the value of y when x = 15a:7b:9c:18d:25

Answer 1

To direct variations use a rule of three, as follow:

`\begin{gathered} (?)/(12)=(15)/(20) \\ \\ ?=12*(15)/(20) \\ \\ ?=(180)/(20) \\ \\ ?=9 \end{gathered}`Then, when x=15, y is 9

Answer: B.9