If there are 3 green marbles and 4 blue marbles in a box, what is the probability that a blind-folded person would pick a blue marble?
You have 4 chances out of 7 of getting a blue marble.
4/7
To calculate the probability of picking a blue marble, we need to know the total number of marbles in the box and the number of blue marbles. In this case, we are given that there are 3 green marbles and 4 blue marbles.
To find the total number of marbles in the box, we simply add the number of green marbles to the number of blue marbles:
Total number of marbles = 3 green marbles + 4 blue marbles = 7 marbles
Now, the probability of picking a blue marble can be calculated by dividing 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) = 4 / 7
Therefore, the probability of picking a blue marble is 4/7 or approximately 0.57 (rounded to two decimal places).