Use the main ratio to find how many of each type of passenger, then apply the sub-ratios.<br><br>
&bull; Adults : Children = 4 : 5, total 72 passengers.<br>
&bull; Adults = \(\frac{4}{9} \times 72 = 32\); Children = \(\frac{5}{9} \times 72 = 40\).<br>
&bull; Adults paying cash = \(\frac{1}{3+1} \times 32 = \frac{1}{4} \times 32 = 8\).<br>
&bull; Children paying cash = \(\frac{3}{2+3} \times 40 = \frac{3}{5} \times 40 = 24\).<br>
&bull; Total paying cash = 8 + 24 = 32.<br><br>
Final Answer: 32