1. **State the problem:** We need to determine if the ratios 10 large bookmarks to 4 small bookmarks and 15 large bookmarks to 6 small bookmarks are equivalent. 2. **Formula and rule:** Two ratios $\frac{a}{b}$ and $\frac{c}{d}$ are equivalent if their cross products are equal, i.e., if $a \times d = b \times c$. 3. **Apply the rule:** For the given ratios, check if $10 \times 6 = 4 \times 15$. 4. **Calculate cross products:** $$10 \times 6 = 60$$ $$4 \times 15 = 60$$ 5. **Compare results:** Since both cross products equal 60, the ratios are equivalent. **Final answer:** Yes, the ratios are equivalent.