Question 829311
Number of red marbles - {{{N[r]}}}
Number of white marbles - {{{N[w]}}}
I assume there are only red and white marbles in the bag.
1.{{{P(r)=(N[r])/(N[r]+N[w])}}}
{{{P(w)=(N[w])/(N[r]+N[w]-1)}}}
So then,
{{{P=P[r]*P[w]}}}
{{{P=(N[r]*N[w])/((N[r]+N[w])(N[r]+N[w]-1))}}}
2.{{{P(r1)=(N[r])/(N[r]+N[w])}}}
{{{P(r2)=(N[r]-1)/(N[r]+N[w]-1)}}}
So then,
{{{P=P[r1]*P[r2]}}}
{{{P=(N[r]*(N[r]-1))/((N[r]+N[w])(N[r]+N[w]-1))}}}