Two quantities $x$ and $y$ satisfy $(3x+2y)/(3x-2y)=5/3$. Then $x:y$ is:

Cross-multiplying, $3(3x+2y)=5(3x-2y)$ → $9x+6y=15x-10y$ → $16y=6x$ → $x/y=16/6=8/3$. (Check: with $x=8$ and $y=3,(24+6)/(24-6)=30/18=5/3$.) Reading 5 : 3 straight off the right-hand side ignores the 3s and 2s attached to $x$ and $y$.