Question

Julie wants to make 800g of a 15% alcohol solution by mixing 20% solution and a 4% solution. How many grams of each kind does she need?

If a 20% and a 4% alcohol solution weigh x g and y g respectively

solve with equation please and show steps thank you ;)

Answer 1

x+y=800; 0.20x+0.04y=0.15×800=120.
y=800-x so 0.20x+0.04(800-x)=120.
0.20x+32-0.04x=120.
0.16x=88 and x=88/0.16=550g making y=250g.