|Ω| = 6 - number of all results
A = {1, 3} → |A| = 2 - number of (a) results
P(A) = 2/6 = 1/3
So,
First you have to distribute the numbers outside of the parentheses (you multiply them with the numbers inside of the parentheses
-18+(-9a) + 8a +36=11
Then collect like terms
18-1a =11
-18 -18
---------------------
-1a=-7
Divide both sides by -1
a=7
Write the coeeficientes of the polynomial in order:
| 1 - 5 6 - 30
|
|
|
------------------------
After some trials you probe with 5
| 1 - 5 6 - 30
|
|
5 | 5 0 30
-----------------------------
1 0 6 0 <---- residue
Given that the residue is 0, 5 is a root.
The quotient is x^2 + 6 = 0, which does not have a real root.
Therefore, 5 is the only root. You can prove it by solving the polynomial x^2 + 6 = 0.
The answer should be C
Because you take the number of young people who work outdoors, which is 242 and divide it by the total, which appeared to be 1028.