Question 347387
given:
{{{.25a + .5b = .45*1000}}}
{{{25a + 50b = 45000
{{{a + b = 1000}}}
{{{25a + 25b = 25000}}}
By subtraction:
{{{25b = 20000}}}
{{{b = 800}}}
{{{a = 1000 - 800}}}
{{{a = 200}}}
200 grams of the 25% copper and 800 grams
of the 50% copper should be used