NES Early Childhood Education Practice Test

Probability is found by comparing how many favorable outcomes there are to the total number of possible outcomes when drawing one item. There are 2 blue marbles out of 8 total marbles, so the chance of drawing blue is 2/8, which simplifies to 1/4. This matches the option showing one-quarter. The other fractions don’t fit because they would imply more or fewer blue marbles relative to the total than actually exist (for example, 1/2 would need half the marbles to be blue, which isn’t the case here; 1/6 would imply about 1.33 blue marbles, which isn’t possible; 2/5 would imply 3.2 blue marbles, also not possible).