now, if we divide 300 by (3+7), we get 10 equal pieces, then we give 3 of those pieces to one side, and 7 of those pieces to the other side.
[tex]\bf \textit{300 at 3:7 ratio}\qquad \cfrac{3\left( \frac{300}{3+7} \right)}{7\left( \frac{300}{3+7} \right)}\implies \cfrac{3\left( \frac{300}{10} \right)}{7\left( \frac{300}{10} \right)}\implies \cfrac{3(30)}{7(30)}\implies \cfrac{90}{210}[/tex]
and of course, 90 + 210 = 300.
