Question

If a bag of marbles contains 6 yellow, 8 blue, and 6 red marbles, then what is the probability of not pulling out a

blue or yellow marble?

Answer 1

Explanation:

a probability is always the ratio

desired cases / totally possible cases.

we have here a total of 6 + 8 + 6 = 20 marbles.

to not pull a blue or yellow marble is in this context the same event as pulling a red marble.

so, the desired cases are 6 (red).

which we can get directly from the 6 red marbles, or by counting off the undesired cases : 20 - 8 - 6 = 6.

and the probabilty for not pulling a blue or yellow marble (or simply pulling a red marble) is

6/20 = 3/10 = 0.3