Question

Devon needs 90mL of a 10% acid solution for a science experiment. He has available a 5% solution and a 20% solution. How many milliliters of the 5% solution and how many milliliters of the 20% solution should he mix to make the 10% solution?

Answer 1

Answer:

Devon needs add 60 mL of 5% acid solution and 30 mL of 20% acid solution

Explanation:

It know acid and water concentration for every solution. 2 equation are proposed because there are two unknowns. V1= volume 5%acid and V2 =volume 20% acid

Acid   V1(0.05)+V2(0.2)=90mL(0.1)

Water   V1(0.95)+V2(0.8)=90mL(0.9)

Clearing V1 from acid equation having to: V1=180-4V2

Replacing V1 in water equation having to: (180-4V2)(095)+V2(0.8)=81

Clearing V2 = 30mL

Replacing in water equation V1(0.05)+30(0.2)=9  So, V1=60mL

I hope it helps