Answer:
A. 35.69%
B. 62.77%
Step-by-step explanation:
In this case, what we must do is calculate the probability supported with the data in the table.
Part A.
What is the probability that a randomly selected student is a 7th grader?
Here the total is all the students that would be the sum of all the grades, which are 325 students.
the number of 7th graders is 116, so the probability is:
116/325 = 0.3569
that is, 35.69%
Part B: What percentage of the students interviewed play Video games?
The total number of students is the same 325 and of those 204 play video games, therefore:
204/325 = 0.6277
that is, 62.77%
a = 4, b = -21, c = -18
to keep from getting "mixed up", evaluate the discriminant first ...
b<sup>2</sup> - 4ac = (-21)<sup>2</sup> - 4(4)(-18) = 729
sqrt(729) = 27
x = (21 +/- 27)/8
x = -3/4, x = 6
since the discriminant is a perfect square, the original quadratic will factor ...
4x<sup>2</sup> - 21x - 18 = 0
(4x + 3)(x - 6) = 0
x = -3/4, x = 6
