Question

A bag contains 6 red, 7 blue, and 5 green coins. If 3 coins are randomly selected in succession, what is the probability of selecting a red coin, then a blue coin, and then a green coin, if replacement occurs each time?

Answer 1

Total coins = 6 + 7 + 5 = 18
Red = 6
Blue = 7
Green = 5

P(Red, then blue, then green) = (6/18)(7/18)(5/18) = 35/972

Answer: 35/972

Answer 2

$|\Omega|=18^3=5832\\ |A|=6\cdot7\cdot5=210\\\\ P(A)=\dfrac{210}{5832}=\dfrac{35}{972}\approx3.6\%$