1.Let's say that there are three sellers and three buyers in the market for lightly pre-owned masks, each willing to sell or buy a single mask.The first, second and third sellers have respective willingness to sell of $6, $1 and $5 each.The first, second and third buyers have respective willingness to buy of $7, $8, and $4 each.

a.What is the highest possible total surplus achievable by making exchanges in this market?