A bag contains 6 red marbles, 7 blue marbles and 8 green marbles. If three marbles are drawn out of the bag, what is the exact probability that all three marbles drawn will be blue?Answer:
Q. A bag contains 6 red marbles, 7 blue marbles and 8 green marbles. If three marbles are drawn out of the bag, what is the exact probability that all three marbles drawn will be blue?Answer:
Determine total number of marbles: Determine the total number of marbles in the bag.The bag contains 6 red marbles, 7 blue marbles, and 8 green marbles. So, the total number of marbles is 6+7+8.
Calculate total number of marbles: Calculate the total number of marbles.6 red + 7 blue + 8 green = 21 total marbles.
Determine probability of drawing one blue marble: Determine the probability of drawing one blue marble.The probability of drawing one blue marble is the number of blue marbles divided by the total number of marbles, which is 217.
Determine probability of drawing a second blue marble: Determine the probability of drawing a second blue marble after one has already been drawn.After drawing one blue marble, there are now 6 blue marbles left and 20 total marbles. The probability of drawing a second blue marble is now 206.
Determine probability of drawing a third blue marble: Determine the probability of drawing a third blue marble after two have already been drawn.After drawing two blue marbles, there are now 5 blue marbles left and 19 total marbles. The probability of drawing a third blue marble is now 195.
Calculate probability of drawing three blue marbles in a row: Calculate the probability of drawing three blue marbles in a row.The probability of drawing three blue marbles consecutively is the product of the probabilities of each draw:(217)×(206)×(195).
Simplify the probability: Simplify the probability.(217)×(206)×(195)=(31)×(103)×(195)=(3×10×191×3×5)=1905=381.
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