30%=.3 20%=.2 27%=.27
our unknown is the weight if the 30% and the total weight if the resulting alloy is 25+our unknown
we will call our unknown x, so
[tex]x \times .3 + 25 \times .2 = (x + 25) \times .27[/tex]
solve for x
[tex].3x + 5.0 = .27x + 6.75 \\ .3x - .27x + 5.0 = .27x - .27x + 6.75 \\ .03x + 5.0 = 6.75 \\ .03x + 5.0 - 5.0 = 6.75 - 5.0 \\ .03x = 1.75 \\ \frac{.03x}{.03} = \frac{1.75}{.03} \\ x = 58.33[/tex]
