Two weeks ago Rose and Harper made Christmas cards for all of my students. The night before I was going to give them out, Bruno and Boostie chewed up 3/4ths of
them. The girls made new ones to replace the ones that were chewed. They could
only make 14. I only had 65 to bring to school.
How many cards did I have to begin with?

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.

126 maybe. sorry