bro help i suck at math what is the answer to this?

Question

A bag contains 12 gray and 24 white marbles. A marble is drawn at random.

What is the theoretical probability, as a decimal, of drawing a gray marble? Round the decimal to the nearest hundredth.

Answer 1

                               #gray marbles

P (gray marble) = -----------------------

                              total #marbles

                                   12

                          = ------------

                               12 + 24

                              12

                          = -----

                              36

                         = 0.33              ..........ANS

Answer 2

You have a total of 36 marbles. The probability of drawing any one particular marble is 1 in 36. As there are 12 grey marbles, the probability that marble will be grey is 12 in 36.

Ans: 12/36 = 1/3 = 0.333_