Question

A bag contains 5 red marbles, 4 blue marbles, 3 green marbles, and no other marbles. If a marble is chosen at random from the bag, what is the probability that the marble chosen will not be red?

Answer 1

Answer:

A = choosing a red marble

B = choosing a green marble

Probability of A happening = P(A) = 5/(3+5+4) = 5/12

Probability of B happening = P(B) = 4/(3+5+4) = 4/12

Probability of either happening = P(A) + P(B) = 5/12 + 4/12 = 7/12

The key word in their question is red OR green and that is why we add the two probabilities. If they ask the probability of them both happening (if they said red AND green), you would multiply P(A)*P(B).

Answer 2

The probability that the chosen marble is not red is $\frac{7}{12}$.

What is probability?

A probability is a number that reflects the chance or likelihood that a particular event will occur.

What is the formula for the probability?

The formula of the probability is

$P(E) = \frac{Number\ of\ favorable\ outcomes}{Total\ number\ of\ outcomes }$

Where, P(E) is the probability of an event.

According to the given question.

Number of red marbles = 5

Number of blue marbles = 4

Number of green marbles = 3

So,

The total number of marbles in a bag = 5+4+3 = 12

And, the probability that chosen marble is red = $\frac{5}{12}$

Therefore,

the probability that the chosen marble is not red

$=1-\frac{5}{12}$

$= \frac{12-5}{12}$

$= \frac{7}{12}$

Hence, the probability that the chosen marble is not red is $\frac{7}{12}$.

Find out more information about probability here:

https://brainly.com/question/11234923

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