A van travels 180 miles on 12 gallons of gas. How many gallons will it need to travel 285 miles?

if a van travels 180 miles / 12 gallons, it travels 15 miles / gallon (simply divide 180 / 12)

285 miles / 15 = 19 gallons

The van will need 19 gallons to travel 285 miles.

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.