Let the number of floor tickets sold be x.
Let the number of balcony tickets sold be y.
According to the first condition,

The total amount collected is $ 14000.
According to the second condition,

Multiplying equation (1) by 20,

Subtracting equation (3) from (2),

Substituting x = 400 in equation (1),

Thus a number of floor tickets sold is 100 and the number of balcony tickets sold is 400.