Rs.558 is divided into 33 girls and 21 boys so that share of girl and boy is 5:1 then find the share of a girl ?

Let the share of a boy be 'x' and the share of a girl be '5x'
The sum of amount with boys = $$21\times x=21x$$
The sum of amount with girls = $$33\times 5x=165x$$
The total amount of money = 21x+165x = 186x
But we know that this amount is Rs. 558
=> 186x = 558
=> x = 3
The share of a girl = 5x = $$5\times3=Rs. 15$$