Question

A jeweler wants to make 1600 grams of 25% silver compound by mixing 20% and 40% silver compounds together. How many grams of each kind will she need?

Answer 1

You need 1600 grams so
x + y = 1600
.20x + .40y = .25(1600)

x + y = 1600
20x + 40y = 25(1600) multiplied by 100

x + y = 1600
20x + 40y = 40000

-20x - 20y = -32000 multiplied by -20
20x + 40y = 40000

20y = 8000
y = 400

x + y = 1600
x + 400 = 1600
x = 1200

So 1200 grams of the 20%
400 grams of the 40%

Answer 2

thanks