Solution:
Given:
Let x represent children tickets
Let y represent adult tickets
Hence,
[tex]\begin{gathered} Total\text{ of 62 tickets sold means;} \\ x+y=62 \\ \\ \\ Total\text{ c}ost\text{ of children ticket is \$}3.50x \\ Total\text{ }cost\text{ of adult ticket is \$}7.50y \\ \\ Total\text{ tickets sold cost \$365.00. This means;} \\ 3.5x+7.5y=365 \end{gathered}[/tex]Solving the two equations simultaneously;
[tex]\begin{gathered} x+y=62.............................(1) \\ 3.5x+7.5y=365..........................(2) \\ \\ From\text{ \lparen1\rparen,} \\ y=62-x \\ \\ Substitute\text{ y into equation \lparen2\rparen;} \\ 3.5x+7.5(62-x)=365 \\ 3.5x+465-7.5x=365 \\ 465-365=7.5x-3.5x \\ 100=4x \\ \frac{100}{4}=x \\ x=25 \\ \\ 25+y=62 \\ y=62-25 \\ y=37 \end{gathered}[/tex]x = children tickets = 25
y = adult tickets = 37
Therefore, 25 children tickets were sold.