Question

4.5 g of an alloy of copper and zinc contains 3.5 g of copper. What weight of copper will there be in 18.9 g of the alloy?

Answer 1

Let the weight of copper be x g.
​Then, 4.5:3.5::18.9:x
Product of extremes = Product of means
4.5 × x = 3.5 × 18.9
⇒ x = 66.15 = 14.7
4.5
So, the weight of copper is 14.7 g.