In a bag, the number of ₹5 coins is 8 more than the number on ₹10 coins but 20% less than the number of ₹2 coins. If the total amount in the bag is ₹270, what is the number of ₹5 coins?

Let's assume the number of ₹2, ₹5 and ₹10 coins are 'a', 'b' and 'c' respectively.

In a bag, the number of ₹5 coins is 8 more than the number on ₹10 coins but 20% less than the number of ₹2 coins.

b = c+8

c = (b-8)    Eq.(i)

b = (100-20)% of a

b = 80% of a

b = 0.8a

$$a=\frac{b}{0.8}$$    Eq.(ii)

If the total amount in the bag is ₹270.

2a+5b+10c = 270

Put Eq.(i) and Eq.(ii) in the above equation.

$$2\times\frac{b}{0.8}+5b+10(b-8) = 270$$

$$\frac{b}{0.4}+5b+10b-80=270$$

So the number of ₹5 coins = 20