Kara mixes cups of sugar and water in the ratio of 1:2 to make one liter of lemonade. Calculate the total number of cups of sugar used if she used 84 cups to make lemonade.
The total ratio for the cups of sugar and water needed to make lemonade is 1+2 = <<1+2=3>>3
In the 3 cups needed to make one liter of lemonade, the fraction representing the cups of sugar needed is 1/3.
If she used 84 cups while making lemonade, she used 1/3*84 = <<84*1/3=28>>28 cups of sugar.
#### 28