Main floor ticket is $52
Balcony ticket is $37
Mezzanine ticket is $31
Let x represent main floor tickets
Let y represent balcony tickets
Let z represent main mezzanine tickets
On a particular day, total sales totaled $50512, i.e

There were 86 more main floor tickets sold than balcony and mezzanine tickets combined, i.e

The number of balcony tickets sold is 139 more than 2 times the number of mezzanine tickets sold, i.e

The equatons are

Solving to find the values of x, y and z
From equation (3), make y the subject

Substitute for y into equation (2)

Make x the subject

Substitute for x and y into equation (1)

Substitute for z into equation (5) to find x

Substitute for z into equation (4) to find y

Hence,
The number of main floor tickets (x) sold is 612
The number of balcony tickets (y) sold is 397
The number of mezzanine tickets (z) sold is 129