Answer:
(2, 22 )
Step-by-step explanation:
Given the 2 equations
y = 7x + 8 → (1)
y = x + 20 → (2)
Substitute y = 7x + 8 into (2)
7x + 8 = x + 20 ( subtract x from both sides )
6x + 8 = 20 ( subtract 8 from both sides )
6x = 12 ( divide both sides by 6 )
x = 2
Substitute x = 2 in (2) for corresponding value of y
y = x + 20 = 2 + 20 = 22
Solution is (2, 22 )
Answer:
0/8
Explanation:
There is no number greater than 10 on the spinner, so there is a 0/8 chance that the spinner will land on a number greater than 10.
Answer:
x = 9
Step-by-step explanation:
The two angles are alternate exterior and has same measurement
15(x+1) = 150 divide both sides by 15
x + 1 = 10 subtract 1 from both sides
x = 9
The m in the equation is the slope and the y-intercept is the b.
y=1x-1
y=mx+b
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
