Explanation

Let number of coins = 3x, 5x, 4x
→ Total value = 264
→ $3x+10x+20x=33x=264\Rightarrow x=8$

$\mathrm{<br>}$2 coins = 5x = 5 × 8 = 40 coins
→ Value = 40 × 2 = 80 

So to get 66, x = 6

33x = 264 → x = 8
33x = 198 → x = 6 → 3x = 18 coins → 1 coins = 18

So likely in your example:

• Ratio = 3:5:4

• Total = 198

• x = 6

• 2 coins = 5x = 30 coins

• Value = ₹60

So if 2 coins value = 66, x = 6.6, which is not clea