Respuesta :

Answer:

3/220.

Step-by-step explanation:

To get exactly 50p he must take 2 20p coins and 1 10p coin.

There are 3! /2! = 3 ways of getting  this.

Total number of ways of getting any 3 coins form 12 is 12!/9!3!

= 12*11*10 / 3!

=  220.

So the answer is 3/220.