At a football game 100 students were surveyed about their food and drink purchases. Out of the 100 students surveyed, 70 bought a drink, 60 bought a food item, and 50 bought both a drink and a food item.

A student is chosen at random from the 70 students that bought a drink. What is the probability that the student also bought a food item?

The probability is 5/7

Step-by-step explanation:

Please check the attached files for more explanation

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.