I need help doing these I have no idea on how to do them

Janet is mixing a 15% glucose solution with a 35% glucose solution. this mixture produces 35 liters of a 19% glucose solution. how many liters of the 15% solution is januet using in the mixture? a. 25 liters c. 28 liters b. 7 liters d. 10 liters

Valentina is subtracting from . she finds the lcd to be 15y2. what is valentina's next step?

Cd is the perpendicular bisector of both xy and st, and cy=20. find xy.