For simplicity, consider a monopolist with no costs whatsoever, thus profit is revenue, which is just price multiplied by quantity. Demand consists of two groups. There are 14 adults: 10 are willing to pay $30 and 4 are willing to pay $20. There are also 16 children: 6 are willing to pay $20 and 10 willing to pay $10.
a. What is best single (uniform for both, adults and children) price to charge? Hint: Guess and check, and focus on either $10, $20, or $30 as the price.
b. What if monopolist could price discriminate by setting different price for each group? How much should it charge adults and how much should it charge children?