At the airport, ten people are waiting on standby. Two seats become available, one first class and one coach. How
many ways are there to fill the two seats?
10
20
45
90

Damon makes 20 cups of lemonade by mixing lemon juice and water. the ratio of lemon juice to water is shown in the tape diagram. lemon juice\text{lemon juice} lemon juice water\text{water} water how much lemon juice did damon use in the lemonade? cups