Answer:
The probability is 0.1 (or 10%)
Step-by-step explanation:
The probability is the ratio of the number of favorable outcomes and the total number of possible outcomes.
The favorable count is determined as follows: we are considering Green marbles. There are 7 of them in the box, so 7 possible picks at the first draw. Since you don't replace the pick, at the next drawing there are only 6 Green ones. So for each of the 7 possible first picks, there are 6 possible second picks: number of possibilities is 7 by 6 = 42.
The total number of possible drawings, irrespective of color is determined as follows: there are 21 marbles in total at first drawing, and 20 at second. So, for each first pick there are 20 possibilities, i.e., total number is 21 by 20 = 420
The probability is therefore:
P = 42 / 420 = 1 / 10 = 0.1 (or 10%)
