# Question 68f7a

Aug 27, 2017

$y = 143$

#### Explanation:

$\text{the initial statement is } y \propto x$

$\text{to convert to an equation multiply by k the constant}$
$\text{of variation}$

$\Rightarrow y = k x$

$\text{to find k use the given condition}$

$y = 39 \text{ when } x = 3$

$y = k x \Rightarrow k = \frac{y}{x} = \frac{39}{3} = 13$

$\text{equation is } \textcolor{red}{\overline{\underline{| \textcolor{w h i t e}{\frac{2}{2}} \textcolor{b l a c k}{y = 13 x} \textcolor{w h i t e}{\frac{2}{2}} |}}}$

$\text{when } x = 11$

$y = 13 \times 11 = 143$

Aug 27, 2017

$y = 143$

#### Explanation:

 y prop x or y = k*x or k = y/x ; y=39 , x =3 :. k =39/3=13 

$k$ is known as variation constant. Variation equation is

 y/x =13 ; x =11 , y = ? :. y/11 =13 or y = 13*11 = 143 #

$y = 143$ [Ans]