You can
put this solution on YOUR website!Let

= grams of copper in bracelet
Let

= grams of gold in bracelet
given:
(1)

g
(2)

cm3
This is 2 equations and 2 unknowns, so it's solvable
Multiply both sides of (2) by

(2)

Multiply both sides of (1) by

and subtract from (2)
(2)

(1)

45 grams of copper are mixed with the gold
check answer:
(1)

(2)

(2)

OK