A hairdyemade by blending a 8% hydro peroxide solution a 4% hydro peroxide solutio. How many m of each are used to make a 200m solution is 7% hydrogen peroxide?

Question

need answer for 8% and need answer for 4%

Answer 1

I will assume you meant ml and not meters, since meters measure length.

Let x = number of ml of 8% solution

Let y = number of ml of 4% solution

x+y = 200     x = 200-y

.08x+.04y = 200(.07)

Multiply both sides of the above equation by 100.

8x+4y = 1400

Replace x with 200-y

8(200-y)+4y = 1400

1600 - 8y + 4y = 1400

                  -4y = -200

                      y = 50 milliliters

x = 200-y

x = 200 - 50

x = 150 ml