Question

The ratio of weights of zinc and copper in an alloy is 5:8. If the weight of copper in a sample of this alloy is 12 g, what is the weight of zinc?

• A. 7 g
• B. 7.5 g
• C. 6.5 g
• D. 6 g

Answer 1

The correct option is B

7.5 g

Given : Ratio of weights of zinc and copper = 5 : 8
Let the weight of zinc for 8 g of copper be 'x'.
Using the concept of equivalent ratios,
$\frac{Zinc}{Copper}$ = $\frac{5}{8}$ = $\frac{x}{12}$
<!--td {border: 1px solid #ccc;}br {mso-data-placement:same-cell;}--> ⇒ x = $\frac{5\times 12}{8}$
× = 7.5 g
$\therefore$ The weight of zinc is 7.5 g.