Bert has a bag with 12 blue marbles, 6 green marbles, 8 purple marbles, and 4 red marbles. If he want the probability of picking a blue marble to be 1/2 what should he do?
Right now the probability of picking blue would be 12/30. If you add another blue it would be 13/31, then 14/32, 15/33, 16/34, 17/35, 18/36. 18/36=1/2, so if he wants the probability to be 1/2 he needs to add 6 more blue.
To find the probability of picking a blue marble, we need to determine the total number of marbles in Bert's bag and the number of blue marbles.
Given that Bert has 12 blue marbles, 6 green marbles, 8 purple marbles, and 4 red marbles, the total number of marbles in the bag is 12 + 6 + 8 + 4 = 30.
To calculate the probability of picking a blue marble, we divide the number of blue marbles by the total number of marbles:
Probability of picking a blue marble = Number of blue marbles / Total number of marbles
Let's denote the probability of picking a blue marble as P(blue). According to the problem, we want P(blue) to be 1/2. Therefore, we can set up the equation:
P(blue) = 1/2
Number of blue marbles / Total number of marbles = 1/2
Number of blue marbles / 30 = 1/2
To find the number of blue marbles that satisfies this equation, we can rearrange the equation:
Number of blue marbles = (1/2) * 30
Number of blue marbles = 15
So, Bert should have 15 blue marbles in his bag if he wants the probability of picking a blue marble to be 1/2.