A bag contains 600 coins of 25p denomination and 1200 coins of 50p denomination. If 12% of 25p coins and 24% of 50p are removed, the percentage of money removed from the bag is nearly :

Answer: Option C

Total money :
$$\begin{array}{rl}& =\text{Rs}\text{. }\left(600\times \frac{25}{100}+1200\times \frac{50}{100}\right)\\ & =\text{Rs}\text{. 750}\end{array}$$
25 paise coins removed :
$$\begin{array}{rl}& =\left(\frac{12}{100}\times 600\right)\\ & =72\end{array}$$
50 paise coins removed :
$$\begin{array}{rl}& =\left(\frac{24}{100}\times 1200\right)\\ & =288\end{array}$$
Money removed :
$$\begin{array}{rl}& =\text{Rs}\text{. }\left(72\times \frac{25}{100}+288\times \frac{50}{100}\right)\\ & =\text{Rs}\text{. 162}\end{array}$$
∴ Required percentage :
$$\begin{array}{rl}& =\left(\frac{162}{750}\times 100\right)\%\\ & =21.6\%\end{array}$$