Your little sister wants to have a lemonade stand this summer. She has decided to sell
each glass of lemonade for $0.25. You help her determine the cost to make each glass
of lemonade to be about $0.10. Mom takes her to the store and buys $15 worth of
supplies to get started. How many glasses of lemonade must she sell to break even?
(She has to pay mom back for the supplies.) Show your work!!