Question

A bag contains 5 red marbles and 7 blue marbles. You randomly pick a marble and then pick a second without returning the marbles to the bag. Both marbles are red.

Answer 1

Probability(both marbles are red) = 5/12 * 4/11 = 20/132

= 5/33 Answer

Answer 2

$|\Omega|=12\cdot11=132\\ |A|=5\cdot4=20\\\\ P(A)=\dfrac{20}{132}=\dfrac{5}{33}\approx15\%$