What is the value of x?

x = 5

Step-by-step explanation:

Using similar triangles theorem

In similar triangles, ratio of their corresponding sides are equal.

Let the point where a line cuts BC = D

Length (AB/BD) = length(AC/CD)

15/3x = 9/(2x-1)

Cross multiply

15(2x-1) = 9(3x)

Expand the brackets

30x -15 = 27x

Collecting like terms

30x-27x = 15

3x = 15

Divide through by 3

x= 15/3

x= 5

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.