Answer:
Explanation:
The colour of the ‘non-green’ marbles is immaterial so the question comes down to the probability of not drawing any green marbles from a bag containing 5 green marbles and 12 (8+4) non-green marbles.
This can be re-worded as the probability of randomly drawing 4 non-green marbles from a bag initially containing 17 (12+5) marbles.
The probability of the first being non-green is 12/17.
For the second the number of non-green marbles reduces, as does the total number of marbles giving a probability of 11/16
For the third (similar) 10/15For the fourth 9/14
The probability of making these 4 successive picks is the product of the individual probabilities = 12/17 * 11/16 * 10/15 * 9/14 = 11880/57120 = 99/476 = 20.8% (approx.)