Question

Zinc and copper are in the ratio of 5 : 3 in 200 gm of an alloy. How much gm of copper be added to make the ratio of 3 : 5?

• A. $133\frac{1}{3}$
  
• B. $\frac{1}{200}$
  
• C. 72
• D. 66
• E. None of these

Answer 1

The correct option is A $133\frac{1}{3}$


Weight of zinc $=200\times \frac{3}{8}=75gm$
Let the ratio of 125 gm zinc and x gm copper be 3 : 5
$\therefore \frac{125}{x}=\frac{3}{5}\therefore x=\frac{125\times 5}{3}=\frac{625}{3}gm$
$\therefore$ Addition of copper in mixture.
$\frac{625}{3}-75=\frac{625-225}{3}=\frac{400}{3}=133\frac{1}{3}gm.$