Michael H. answered 03/22/19
All levels of undergraduate mathematics and statistics
Let x be the number of lower reserved tickets.
Then the number of upper reserved tickets is 345 – x.
The revenue from lower reserved tickets is x · $9.50.
The revenue from upper reserved tickets is (345 – x) · $8.00
The total revenue is therefore x · $9.50 + (345 – x) · $8.00.
So we have (x · $9.50) + (345 – x) · $8.00 = $2809.50.
This simplifies to $1.50 x + $2760 = $2809.50.
Subtracting $2760 from both sides, we get $1.50 x = $49.50.
Then dividing each side by $1.50, we get 33.
Thus there were 33 lower reserved tickes and 312 upper reserved tickets.
You can check that by arithmetic, thus:
(33 · $9.50) + (312 · $8.00) = $2809.50.
Elio A.
Thank you very much!03/22/19