Answer: The answer is 6/15 though, it can be simplified in two different ways. 6/15 simplifies to the fractions 9/15 and 3/5. If the answer is not 6/15 then it must be one of those two fractions.
Step-by-step explanation: There are 15 total marbles in the bag, and 6 of them are blue. Therefore, the probability of selecting a blue marble on the first draw is 6/15. The probability of not selecting a blue marble on the first draw is 1 - 6/15, which simplifies to 9/15 or 3/5.