Answer:
Devon needs to add 60 mL of 5% acid solution and 30 mL of 20% acid solution
Step-by-step explanation:
It knows acid and water concentration for every solution. 2 equations 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 the 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
