12 marbles are in a bag; 3 each of red, blue, green, and orange. If 3 marbles are chosen at random, what is the probability that all 3 are green?

Respuesta :

Answer: [tex]\dfrac{1}{220}[/tex]

Step-by-step explanation:

Given

There are 3 marbles of red, blue, green and orange

Total marbles are 12

No of ways of choosing 3 green marbles out of 3 green marbles is [tex]^3C_3[/tex]

Total no of ways of selecting 3 marbles out of 12 are [tex]^{12}C_3[/tex]

So, the probability is

[tex]\Rightarrow P=\dfrac{^3C_3}{^{12}C_3}=\dfrac{1\times 3\times 2\times 1}{12\times 11\times 10}\\\\\Rightarrow P=\dfrac{1}{220}[/tex]