20. Five mark exercise problems IX

There are $12$ pieces of five, ten and twenty rupee currencies whose total value is $₹105$. But when the first $2$ sorts are interchanged in their numbers, their value will be increased by $₹20$. Find the number of currencies in each sort.

 

 

The number of $₹5$ currencies is .

 

The number of $₹10$ currencies is .

 

The number of $₹20$ currencies is .