Question 176352
Let's look at the language. 
"is" means equals (=)
"ratio of 2x to 5y" means
{{{(2x)/(5y)}}}
Let's put it all together.
{{{(2x)/(5y)=3/4}}}
You're looking for
{{{x/y}}}
Multiply both sides of eq. 1 by (5/2),

{{{(2x)/(5y)=3/4}}}
{{{(5/2)((2x)/(5y))=(3/4)(5/2)}}}
{{{x/y=15/8}}}