Question 640801

If {{{y1 = 5}}} when {{{x1 = 2}}}, find {{{y}}}, when {{{x=4}}} 

{{{only}}} in case that  {{{y}}} varies directly as {{{x}}}

we could also write this as a proportion:

{{{x1/y1=x/y}}}

{{{2/5 = 4/y}}}

{{{2y = 4*5}}}

{{{2y = 20}}}

{{{y = 10}}}