help! math solution I am confused on

Question

You need 160 mL of a 25% alcohol solution. On hand, you have 10% alcohol mixture. You also have 50% alcohol mixture. How much of each mixture will you need to add to obtain the desired solution?

You will need

 __________mL of the 10% solution

__________ mL of the 50% solution

Answer 1

160(25) = 10X + 50Y

X+Y = 160

Y=160-X

4000 = 10X + 50(160-X) = 10X + 8000 - 50X

40X = 4000

X = 100 ml of 10%

Y=160-100 = 60 ml of 50%