In a bag there 28 marbles.
7 black
6 pink
5 blue
4 purple
3 yellow
2 green
1 white
You randomly pick one marble from the bag.
What is P(not black)?
21%
75%
7%
25%
To find the probability of not picking a black marble, we need to calculate the probability of picking a marble that is not black out of the total number of marbles.
The total number of marbles in the bag is 28.
The number of black marbles is 7.
So, the number of marbles that are not black is 28 - 7 = 21.
The probability of picking a marble that is not black is 21/28.
Converting this to a percentage, we get (21/28) * 100 = 75%.
Therefore, the correct answer is 75%.
To find the probability of picking a marble that is not black, we need to first calculate the total number of marbles in the bag that are not black.
Total number of marbles = 28
Number of black marbles = 7
Number of marbles that are not black = Total number of marbles - Number of black marbles = 28 - 7 = 21
Now, the probability of picking a marble that is not black can be calculated by dividing the number of marbles that are not black by the total number of marbles.
P(not black) = Number of marbles that are not black / Total number of marbles
P(not black) = 21 / 28
To simplify the fraction, we can divide both the numerator and the denominator by their greatest common divisor, which is 7.
P(not black) = (21 ÷ 7) / (28 ÷ 7)
P(not black) = 3 / 4
To express this as a percentage, we convert the fraction to a decimal by dividing the numerator by the denominator:
P(not black) = 3 ÷ 4 = 0.75
Converting the decimal to a percentage:
P(not black) = 0.75 × 100% = 75%
Therefore, the probability of randomly picking a marble that is not black is 75%.