4(2a+3) = 8a+ 12
This represents the distribution property because it multiplies everything in the parentheses. 4 X 2a = 8a 4X3=12
Answer:
b) f (-1) ese es el resultado
The value of Sin(a) suppose that Cos B = 0.68 in which case, a + B = 90° is; 0.68.
<h3>Trigonometry</h3>
First, when we have two angles, whose sum equals, 90°.
In essence, Since the algebraic sum of angles A and B is 90°;
By trigonometric identity;
Where; (90 - A) = B.
Therefore; Sin A = Cos B = 0.68.
Read more on trigonometry;
brainly.com/question/20519838
Population = 135 students
Mean score = 72.3
Standard deviation of the scores = 6.5
Part (a): Students from 2SD and 3SD above the mean
2SD below and above the mean includes 95% of the population while 3SD includes 99.7% of the population.
95% of population = 0.95*135 ≈ 129 students
99.7% of population = 0.997*135 ≈ 135 students
Therefore, number of students from 2SD to 3SD above and below the bean = 135 - 129 = 6 students.
In this regard, Students between 2SD and 3SD above the mean = 6/2 = 3 students
Part (b): Students who scored between 65.8 and 72.3
The first step is to calculate Z values
That is,
Z = (mean-X)/SD
Z at 65.8 = (72.3-65.8)/6.5 = 1
Z at 72.3 = (72.3-72.3)/6.5 = 0
Second step is to find the percentages at the Z values from Z table.
That is,
Percentage of population at Z(65.8) = 0.8413 = 84.13%
Percentage of population at (Z(72.3) = 0.5 = 50%
Third step is to calculate number of students at each percentage.
That is,
At 84.13%, number of students = 0.8413*135 ≈ 114
At 50%, number of students = 0.5*135 ≈ 68
Therefore, students who scored between 65.8 and 72.3 = 114-68 = 46 students
Answer:Tiffany has 28 Justin has 64
Step-by-step explanation:
64+28=92
