How many grams of copper are in the the resulting mixture?

Question

An alloy is a mixture of metals. Suppose that a certain alloy is made by mixing 200
grams of an alloy containing 45% copper with 120 grams of an alloy containing 75% copper.

Answer 1

First alloy:  200 g x 0.45 Cu = 90 g of Cu

Second alloy:  120 g x 0.75 Cu = 90 g Cu

Final mixture = 320 g containing 180 g copper (56% copper)