A goldsmith has two alloys that are different purities of gold. The first is 3/4 pure and the second is 5/12 pure. How many ounces of each should be melted and mixed in order to obtain a 6 oz mixture that is 2/3 pure gold?

4 answers

solve
(3/4)x + (5/12)(6-x) = (2/3)(6) ,each term times 12

9x + 5(6-x) = 48
etc
Since there are different quantities of each purity wouldn't there be an x and a y in the equation instead of both being x?
Ok,
x + y = 6 ----> y = 6-x

(3/4)x + (5/12)y = (2/3)(6)

sub in the value of y

mmmhhh!
oooh. okay! thanks!