1. **State the problem:** We need to find which ratios are equivalent to 15:9. 2. **Formula and rule:** Two ratios $a:b$ and $c:d$ are equivalent if $\frac{a}{b} = \frac{c}{d}$. 3. **Simplify the given ratio:** Simplify 15:9 by dividing both terms by their greatest common divisor (GCD), which is 3. $$\frac{15}{9} = \frac{\cancel{3}5}{\cancel{3}3} = \frac{5}{3}$$ 4. **Check each ratio:** - 17:11: $$\frac{17}{11} \neq \frac{5}{3}$$ - 5:3: $$\frac{5}{3} = \frac{5}{3}$$ (Equivalent) - 30:18: Simplify by dividing numerator and denominator by 6: $$\frac{30}{18} = \frac{\cancel{6}5}{\cancel{6}3} = \frac{5}{3}$$ (Equivalent) - 16:10: Simplify by dividing numerator and denominator by 2: $$\frac{16}{10} = \frac{\cancel{2}8}{\cancel{2}5} = \frac{8}{5} \neq \frac{5}{3}$$ - 60:36: Simplify by dividing numerator and denominator by 12: $$\frac{60}{36} = \frac{\cancel{12}5}{\cancel{12}3} = \frac{5}{3}$$ (Equivalent) 5. **Final answer:** The ratios equivalent to 15:9 are 5:3, 30:18, and 60:36.