You need to know the proportion of members to non members or it is not
solvable.

See the following examples. Shows that the price changes significantly with
the proportion of members to non members.

Category           Number    Ticket price       Break even amount
non members      200           $20.00          $4,000.00
           
           
non members      100            $22.85          $2,285.00
members            100            $17.15          $1,715.00
                                                              $4,000.00
           
non members        50             $24.65          $1,232.50
members             150               $18.45          $2,767.50
                                                               $4,000.00