Question

There are 40 pieces of building blocks in a bag: 10 each of blue, green, red, and yellow. Two pieces are chosen at random. Identify the probability that both of the pieces chosen are green.

Answer 1

`\displaystyle |\Omega|=\binom{40}{2}=(40!)/(2!38!)=(39\cdot40)/(2)=780\\|A|=\binom{10}{2}=(10!)/(2!8!)=(9\cdot10)/(2)=45\\\\P(A)=(45)/(780)=(3)/(52)\approx5,8\%`