Question 1117619
Maybe, add x to numerator and denominator,
{{{(1+x)/(4+x)=3/4}}}, to get the amount of brown sugar, cups





-----------------------this, misunderstanding of the description-----------

The butter:

{{{(1+x)/(4+x)}}}



The amount of brown sugar needed would be

{{{((1+x)/(4+x))((3)/(1))}}}


{{{3(x+1)/(x+4)}}} {{{cups}}}