Respuesta :
The total number of choices available are : 12 gray + 24 white
the total choices we have = 36 marbles ( all taken together
We want to pick a gray marble in only one attempt
so the favourable items = number gray marbles = 12
probability of choosing a gray marble =
number of favourable marbles/ total number of choices available
12/ 36 = 1/3
Answer is 1/3 = 0.33
[tex] |\Omega|=36\\
|A|=12\\\\
P(A)=\dfrac{12}{36}=\dfrac{1}{3}\approx0.33 [/tex]