Why is the fruit fly an ideal organism for genetic research?

total amount spent on student ticket = 186($2.5)=$465.00,

Total amount spent on adult tickets = 135($3.5)=$472.50

Explanation:

cost total = student ticket price (x) + adult ticket price (321 - x)

$937.50 = (2.5)(x) + (3.5)(321 - x)

$937.50 = 2.5x + 1123.5 - 3.5x

x = 186, therefore 186 student tickets sold,  

(321-x) = 321-186 = 135, therefore 135 adult tickets were sold.

total amount spent on student ticket = 186($2.5)=$465.00,

Total amount spent on adult tickets = 135($3.5)=$472.50

So the total amount spent on tickets was  

$472.50 + $465.00 = $937.50