Question 1080750


if {{{y}}} varies {{{directly}}} as {{{x}}}, we have

{{{y=kx}}} 

If {{{x = 20}}} when {{{y = 5}}},we can find {{{k}}}:

{{{5=20k}}}

{{{5/20=k}}}

{{{k=1/4}}}


so,  {{{x}}} when {{{y= 9 }}} will be:

{{{9=(1/4)x}}} 

{{{x=9*4}}}

{{{x=36}}}