If there are 10 red marbles and 30 blue, what is the probability of randomly selecting a blue marble?
Of the 40 marbles you have, 30 of them are blue, so
Prob(blue) = 30/40 = 3/4 or .75
To calculate the probability of randomly selecting a blue marble, we need to determine the total number of marbles and the number of blue marbles.
In this case, the total number of marbles is 10 red + 30 blue = 40 marbles.
The probability of randomly selecting a blue marble can be calculated by dividing the number of blue marbles by the total number of marbles:
Probability = Number of blue marbles / Total number of marbles
So the probability of randomly selecting a blue marble is:
Probability = 30 blue marbles / 40 total marbles
Simplifying this fraction gives:
Probability = 3/4 or 0.75 (or 75%)
Therefore, the probability of randomly selecting a blue marble is 0.75 or 75%.