A bag contains 5 red, 3 blue, and 2 green marbles. If one marble is drawn at random, what is the probability that it is NOT blue?

✓ Correct Answer: Option C

Total marbles = 5 + 3 + 2 = 10. The number of marbles that are NOT blue (red or green) is 5 + 2 = 7. The probability of drawing a non-blue marble is the number of non-blue marbles divided by the total, which is 7/10.