Respuesta :

apologiabiology
there are 3 urns

5 possible choices for first urn
4 for 2nd (because we used one for the first urn)
3 for 3rd (because we used 2 for first and 2nd urns)

so there are 5*4*3 or 60 different ways to place 5 balls into 3 indistinguisable urns