Question 92176
let s=silver, c=copper ... 50s+40c=220 ... 25s+30c=140 ... multiplying second equation by -2 and adding to first equation gives


50s+40c-2(25s+30c)=220-2(140) ... 50s+40c-50s-60c=220-280 ... -20c=-60 ... c=3


50s+40(3)=220 ... 50s+120=220 ... 50s=100 ... s=2