The first thing we must do for this case is find the number of total guitarists.
We have then:

We now look for the relationship between the number of guitarists playing jazz alone to the total number of guitarists.
We have then:

Where,
x: number of guitarists playing jazz alone
From here, we clear the value of x.

Then, the number of guitarists who play classical solo is:

Answer:
30 guitarists play classical solos in the contest
Average rate of change means find the slope of the secant line. So if there is a function f(x) and you want to find the average R.O.C over the interval [a,b], it would be (f(b)-f(a))/(b-a)
1. (f(3)-f(1))/(3-1)= (0-(-2))/2= 1, so D.
2. Same concept; (8-4)/(3-1)=2, so A.
3. Again, (39-(-1))/5= 8, B.
The probability of multiple events happening is calculated by multiplying the probabilities of each event together. This is the case if each event is independent of the other events.
For a fair coin, the probability of tails is 1/ 2 or 0.5, so the probability of all tails in 10 tosess is (1/2)^10 = 1/1024 = 0.0009765625
Correct answer: D