Question

A chemist mixes a 10% hydrogen peroxide solution with a 25% hydrogen peroxide solution to create 30 liters of a 15% hydrogen peroxide solution. How many liters of the 10% solution did the chemist use to make the 15% solution?

Answer 1

X+y= 30
Y=30-X
.15(30)= 4.50
.10x+.25(30-X)=4.50
.10x+7.50-.25x=4.50
-.15x=4.50-7.50
-.15x=-3
Divide by -.5
X=20

Answer 2

The answer is 20 l. Seethe solution on the photo.