A quantity b varies jointly with c and d and inversely with f. When c is 4, d is 9, and f is 6, b is 18. What is the constant of variation?

k = 3

Step-by-step explanation:

Given that b varies jointly with c and d and inversely with f then the equation relating them is

b = ← k is the constant of variation

To find k use the condition c = 4, d = 9, f = 6 , b = 18, then

18 = = = 6k ( divide both sides by 6 )

3 = k

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.