we know the ratio of yellow and red tulips are 2 : 3, if there are 100 total, let's simply divide 100 by (2 + 3) and distribute accordingly.
[tex]\stackrel{\textit{\large yellow to red tulips ratio}}{\cfrac{\stackrel{\textit{yellow tulips}}{y}}{\stackrel{\textit{red tulips}}{r}} = \cfrac{2}{3}}\qquad \qquad \cfrac{2\cdot \frac{100}{2+3}}{3\cdot \frac{100}{2+3}}\implies \cfrac{2(20)}{3(20)}\implies \cfrac{\stackrel{yellow}{40}}{\underset{red}{60}}[/tex]
