your friend herman operates a neighborhood lemonade stand. last month he spent $2 and made 19 glasses of lemonade, and another time he spent $5 and made 83 glasses of lemonade. you decide to use this data to create a linear cost function, c(q), giving the cost in dollars of making q glasses of lemonade. if lemonade sells for $0.15 per glass, how many glasses must he sell to break even?