The correct answer is (A)!
Answer:


So then we can conclude that we expect the middle 95% of the values within 18 and 30 minutes for this case
Step-by-step explanation:
For this case we can define the random variable X as the amount of time it takes her to arrive to work and we know that the distribution for X is given by:

And we want to use the empirical rule to estimate the middle 95% of her commute times. And the empirical rule states that we have 68% of the values within one deviation from the mean, 95% of the values within two deviations from the mean and 99.7 % of the values within 3 deviations from the mean. And we can find the limits on this way:


So then we can conclude that we expect the middle 95% of the values within 18 and 30 minutes for this case
Answer:
20%
Step-by-step explanation:
First, I added them up. From the things we know, blue, red, green, yellow combined equals 16 marbles. 20-16 equals 4. So there are 4 white marbles. 4/20 times 5 equals 20/100. So the percent of the marbles that are white is 20%.