We know that there are 25 green marbles in a bag of 40 marbles. Using this, we can say that the probability of pulling a green marble out of the bag is 25/40, or 5/8. To find out how many green marbles Shawna should expect to pull out of the bag after 400 trials, we have to multiply the amount of trials (400) by the probability of pulling out a green marble (5/8).
400 × 5/8 = (400 × 5)/8 = 2000/8 = 250
Shawna should expect 250 green marbles after 400 trials.
