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 = `66.15/4.5` = 14.7

So, the weight of copper is 14.7 g.