Ravi cracked open a savings box of ₹600 made up of ₹1, ₹2 and ₹5 coins in the ratio 1 : 2 : 1 by number. Find the percentage of coins that are ₹2 coins.

Fractions, decimals, and percentages are three notations for the same idea. Convert freely:

- **Fraction → percentage**: multiply by 100. $\frac{3}{5}=\frac{3}{5}\times 100\%=60\%$.
- **Percentage → fraction**: divide by 100 and simplify. $75\%=\frac{75}{100}=\frac{3}{4}$.
- **Decimal → percentage**: shift two places right. 0.34 = 34%.
- **Percentage → decimal**: shift two places left. 8% = 0.08.

With practice, this becomes automatic and you can move between forms without thinking.