Answer:
975 students
Step-by-step explanation:
This is a dense question. Let's look at it piece by piece:
1. The ratio of boys to students in the class is 10/25. If there are 25 students and 15 girls, that leaves 10 boys.
2. The question says that the ratio is in proportion of boys to total students in the school. "In proportion" in this case means that if we convert 10/25 to a fraction with numerator 390, the denominator is the amount of students in school.
3. 10x39=390. What you do the numerator you must do to the denominator: 25x39=975.
4. This means 975 students go to the school.
Answer:
![\left[\begin{array}{ccc}7\\4\\2\end{array}\right]](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D7%5C%5C4%5C%5C2%5Cend%7Barray%7D%5Cright%5D)
The answer is a single-column matrix (7,4,2)
Step-by-step explanation:
In such multiplication of matrices, you have to proceed by multiplying each ROW of the first matrix by the COLUMN of the second matrix. So,
![\left[\begin{array}{ccc}3&6&1\end{array}\right] * \left[\begin{array}{ccc}2\\0\\1\end{array}\right] = (3 * 2) + (6 * 0) + (1 * 1) = 6 + 0 + 1 = 7](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D3%266%261%5Cend%7Barray%7D%5Cright%5D%20%2A%20%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D2%5C%5C0%5C%5C1%5Cend%7Barray%7D%5Cright%5D%20%3D%20%283%20%2A%202%29%20%2B%20%286%20%2A%200%29%20%2B%20%281%20%2A%201%29%20%3D%206%20%2B%200%20%2B%201%20%3D%207)
then...
![\left[\begin{array}{ccc}2&4&0\end{array}\right] * \left[\begin{array}{ccc}2\\0\\1\end{array}\right] = (2 * 2) + (4 * 0) + (0 * 1) = 4 + 0 + 0 = 4](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D2%264%260%5Cend%7Barray%7D%5Cright%5D%20%2A%20%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D2%5C%5C0%5C%5C1%5Cend%7Barray%7D%5Cright%5D%20%3D%20%282%20%2A%202%29%20%2B%20%284%20%2A%200%29%20%2B%20%280%20%2A%201%29%20%3D%204%20%2B%200%20%2B%200%20%3D%204)
and
![\left[\begin{array}{ccc}0&6&2\end{array}\right] * \left[\begin{array}{ccc}2\\0\\1\end{array}\right] = (0 * 2) + (6 * 0) + (2 * 1) = 0 + 0 + 2= 2](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D0%266%262%5Cend%7Barray%7D%5Cright%5D%20%2A%20%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D2%5C%5C0%5C%5C1%5Cend%7Barray%7D%5Cright%5D%20%3D%20%280%20%2A%202%29%20%2B%20%286%20%2A%200%29%20%2B%20%282%20%2A%201%29%20%3D%200%20%2B%200%20%2B%202%3D%202)
I hope it helps.
Answer:
The minimum sample size required to create the specified confidence interval is 2229.
Step-by-step explanation:
We have that to find our
level, that is the subtraction of 1 by the confidence interval divided by 2. So:

Now, we have to find z in the Ztable as such z has a pvalue of
.
So it is z with a pvalue of
, so 
Now, find the margin of error M as such

In which
is the standard deviation of the population and n is the size of the sample.
What is the minimum sample size required to create the specified confidence interval
This is n when 





Rounding up
The minimum sample size required to create the specified confidence interval is 2229.
Answer:

Step-by-step explanation:
Please see attached picture for full solution.
Answer:
12.4 ft
Step-by-step explanation:
Everything is done right so far.
Now to calculate the height of the tree, 12tan46, put the equation into a calculator.
Either a graphing calculator (make sure it is in degrees, not radians),
or the one on your phone (turn your phone landscape in the calculator app to get the trig functions.))
12tan46= 12.4 ft