You can
put this solution on YOUR website!Let

= number of main floor tickets sold
Let

= number of upper level tickets sold
given:
(1)

(2)

There are 2 equations and 2 unknowns. When the
number of equations matches the number of unknowns,
it is solvable.
Multiply both sides of (1) by

and subtract from (2)
(2)

(1)

(3)

(3)

(rounded off)
and
(1)

(1)

(1)

(rounded off)
39,385 mainfloor seats were sold and 10615 upper level
seats were sold
check answer:
(2)

(2)

(2)

(2)

(close enough)
and
(1)

(1)

(1)

OK