Use the main ratio to find how many of each flower, then apply the sub-ratios.<br><br>
&bull; Roses : Lilies = 9 : 7, total 112 flowers.<br>
&bull; Roses = \(\frac{9}{16} \times 112 = 63\); Lilies = \(\frac{7}{16} \times 112 = 49\).<br>
&bull; White roses = \(\frac{4}{5+4} \times 63 = \frac{4}{9} \times 63 = 28\).<br>
&bull; White lilies = \(\frac{4}{3+4} \times 49 = \frac{4}{7} \times 49 = 28\).<br>
&bull; Total white flowers = 28 + 28 = 56.<br><br>
Final Answer: 56