Answer: 168 adult tickets were sold.
Step-by-step explanation:
We know that we can find the number of adult and student tickets sold, with this equation:
[tex]10.50a+3.75b=2071.50[/tex]
Since 82 students attended, we can substitute [tex]b=82[/tex] into the equation and solve for "a", in order to calculate the amount of adult tickets sold.
Then, "a" is:
[tex]10.50a+3.75(82)=2071.50\\\\10.50a+307.5=2071.50\\\\10.50a=2071.50-307.5\\\\a=\frac{1764}{10.50}\\\\a=168[/tex]