Brass is made from a mixture of copper and other elements. A mixture that is 80% copper is combined with a mixture that is 60%, resulting in 100 pounds that is 65% copper. Which equation can be used to find x the amount of 60% mixture used to create the 65% mixture?
0.8 (100-x) + 0.6x = 100(0.65)
0.6(100 -x) + 0.8x = 100(0.65)
0.8(100) + 0.6x =0.65(100 - x)
0.6(x) + 0.8(100 +x) =0.65