Answer:B)
Step-by-step explanation:
Step 1: list down the probability of the marbles,
you will get the probability
of for the blue marbles and for the red ones .
Step 2: <em>Forget</em><em> about the blue marbles and focus on the red marbles </em>
On the first pick of marbles the probability of getting a red marble is but then you didn't replace the marble so now you have only 19 marbles as your total.
Step 3: lets say you picked a red marble on the first pick now you only have 7 red marbles out of 19 marbles (minus the red marble you picked -> step 2)
so the probability of getting a red marble on the second pick is
Step 4: multiply the probabilities of both the first and second pick
it will look like this
×
^ ^
first pick second pick
Note : You will only minus your probability and number of "marbles "( in this case ) if the question says "without replacing "
final answer :