An arena holds 25,000 people. Single and family tickets are sold . The former cost $ 16, the latter covers the cost of 2 adults and 2 kids. The arena is full and generates an income of $365,000. If 1,000 more family tickets were sold, income would decline by $14,000. How many family tickets were sold and @ what cost ? As the price of a single ticket falls by $ 1, the number of tickets sold increases by 1,000. Can it be solved without differentiation ? Does the amount of single tickets decline by 4,000. ? This would cover the capacity constraint. Could you use the formula for price elasticity of demand in micro economics as part of the solution ? Thanks.