Probability question!?

Question

Alright, so a stack of paper contains 200 pieces. 50 of them are yellow. All pieces of paper are mixed up.

If two pieces of paper are taken at random, what is the probability that both will be yellow?

Answer 1

if you are NOT putting the piece back
P(yellow then yellow)=
=P(yellow)*(P(yellow after yellow)
50/200*49/199
=1/4*49/199 =4/396

if you are putting the piece back
then p(yellow then yellow)
=p(yellow)*P(yellow)
=50/200*50/200=1/4*1/4=1/16

Answer 2

One in Four