Chris has a blue coat and a black coat. He has blue pants and brown pants. He has a blue shirt and a red shirt. What's the probability that
he'll wear all of the blue items?

P = 0.125 = 1/8

Step-by-step explanation:

We know that he has a blue coat and a black coat.

If he dresses at random, then the probability of getting the blue coat is equal to the quotient between the number of blue coats (1) and the total number of coats (2).

Then the probability is:

p = 1/2

We also know that he has blue pants and brown pants, the probability of getting at random the blue pants is calculated in the same way than above, then:

q = 1/2

And for the shirt he has a blue shirt and a red one, the probability of randomly selecting the blue one is calculated in the same way than above, then:

k = 1/2

Now, the joint probability (he selects all blue clothes) is equal to the product of the individual probabilities:

P = p*q*k = (1/2)*(1/2)*(1/2) = 1/8 = 0.125

a) one student is chosen from classroom a, then a student is chosen from classroom b.  

step-by-step explanation:

independent events are ones in which the probability of one event does not affect the probability of the second event.

one student is chosen from classroom a; this does not affect the chances of choosing a student from classroom b.   this makes these independent events.

when one card is chosen from a standard deck and then set aside before a second card is chosen, the probability of the second card being chosen changes.   this makes them dependent events.

when one student is chosen from classroom a and then a second student is chosen from classroom a, the probability of choosing the second student changes.   this makes them dependent events.

when a letter is chosen from the alphabet and then a second letter is chosen, the probability of choosing the second letter changes.   this makes them dependent events.