Based on the calculations, the number of blue marbles in this bag is equal to 15 blue marbles.
Given the following data:
In this exercise, you're required to calculate the number of blue marbles considering the fact that the probability of not selecting a blue marble from this bag is ¼.
First of all, we would determine the probability of actually selecting a blue marble from this bag as follows:
Probability = 1 - nP(B).
Probability = 1 - ¼.
Probability = ¾.
Now, we can calculate the number of blue marbles:
P(B) = total number of blue marbles/total number of marbles
¾ = B/20
4B = 60
B = 60/4
Blue marbles, B = 15 blue marbles.
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Answer: 15 marbles
Explanation:
The probability of NOT picking/selecting a blue marble is 1/4. 1/4 of 20 is 5, which means that 5 marbles aren't blue. That leaves 15 marbles, which means that there is a 3/4 probability of selecting a blue marble from the bag (3/4 of 20 is 15).
Therefore, our desired answer is 15 marbles.
