Question 1091802

If x and y vary directly, 

{{{x=ky}}}

and x=10 when y=3, 

{{{x=ky}}}
{{{10=k3}}}
{{{10/3=k}}}
<pre>
Substituting for k in

{{{x=ky}}}
{{{x=expr(10/3)y}}}
</pre>
what will be the value of x when y=9??
<pre>
Substitute 9 for y in

{{{x=expr(10/3)y}}}
{{{x=expr(10/3)(9)}}}

{{{x=expr(10/cross(3))(""^3cross(9))}}}

{{{x=30}}}

Edwin</pre><b>