Answer:
Step-by-step explanation:
Let x represent the amount (in ounces) of 24% alloy in the mix. Then the amount of 12% alloy is (50 -x). The amount of silver in the mix is ...
24%·x + 12%·(50 -x) = 21%·50
12x = 450 . . . . . . simplify, multiply by 100 (to eliminate %), and subtract 600
x = 37.5 . . . . . . . divide by 12
The jeweler needs to mix 37.5 ounces of 24% silver alloy with 12.5 ounces of 12% silver alloy to make 50 ounces of 21% silver alloy.