A mixture contains lemon juice and soda in the ratio 2 : 5. If a new mixture is created by adding this mixture and soda in the ratio 2 : 1, then the ratio of lemon juice and soda in the new mixture is

Let the first mixture have 2x lemon and 5x soda. Adding this to pure soda in a 2:1 ratio means taking 2 parts of the mixture (4x lemon, 10x soda) and 1 part soda (let's say 3y soda). However, the problem implies adding the mixture and soda in a 2:1 ratio by volume; if we take 2 units of the mixture and 1 unit of soda, we have 4 units of lemon and 10+5=15 units of soda (since the mixture is 2/7 lemon and 5/7 soda). The ratio 4:15 is not listed, but if we interpret the ratio as 2 parts mixture to 1 part soda, the calculation leads to 4:17.