Answer:
500
Step-by-step explanation:
It is expected that approximately 500 students would finish the test in less than 40 minutes.
To determine the number of students who would be expected to finish the test in less than 40 minutes, we can use the concept of the standard normal distribution and the z-score.
The z-score measures the number of standard deviations an individual data point is from the mean. In this case, we want to find the proportion of students who finish the test in less than 40 minutes, which corresponds to finding the area under the curve to the left of the mean.
Using the z-score formula:
z = (x - μ) / σ
where x is the value (40 minutes), μ is the mean (40 minutes), and σ is the standard deviation (8 minutes).
Substituting the values into the formula:
z = (40 - 40) / 8
z = 0
A z-score of 0 indicates that the value is exactly at the mean.
Since we are interested in the proportion of students finishing in less than 40 minutes, we need to find the area under the curve to the left of the mean, which is represented by a z-score of 0.
By referring to a standard normal distribution table or using a statistical software, we find that the proportion of students finishing in less than 40 minutes is approximately 0.5000.
To find the expected number of students, we multiply the proportion by the total number of students:
Expected number of students = 0.5000 * 1000 = 500
To learn more about normally distributed click on,
https://brainly.com/question/15415528
#SPJ2
For the function f(x) = –2(x + 3)2 − 1, identify the vertex, domain, and range. The vertex is (3, –1), the domain is all real numbers, and the range is y ≥ –1. The vertex is (3, –1), the domain is all real numbers, and the range is y ≤ –1. The vertex is (–3, –1), the domain is all real numbers, and the range is y ≤ –1. The vertex is (–3, –1), the domain is all real numbers, and the range is y ≥ –1.
we have
[tex]f(x)=-2(x+3)^{2}-1[/tex]
we know that
the equation of a vertical parabola in vertex form is equal to
[tex]y=a(x-h)^{2}+k[/tex]
where
[tex](h,k)[/tex] is the vertex
If [tex]a > 0[/tex] ------> then the parabola open upward (vertex is a minimum)
If [tex]a < 0[/tex] ------> then the parabola open downward (vertex is a maximum)
In this problem
the vertex is the point [tex](-3,-1)[/tex]
[tex]a=-2[/tex]
so
[tex]-2 < 0[/tex] ------> then the parabola open downward (vertex is a maximum)
The domain is the interval-------> (-∞,∞)
that means------> all real numbers
The range is the interval--------> (-∞, -1]
[tex]y\leq-1[/tex]
that means
all real numbers less than or equal to [tex]-1[/tex]
therefore
the answer is
a) the vertex is the point [tex](-3,-1)[/tex]
b) the domain is all real numbers
c) the range is [tex]y\leq-1[/tex]
see the attached figure to better understand the problem
Solve this equation using an algebraic method: (x + 4)( x - 4) = 9
Help me out please
I I'm not good with math
a) total cost = 499 + 49.99x
b) x = 5 games
total cost = 499 + 49.99(5) = 499 + 249.95 = 748.95
4x-5=4x+10 solve for x
The equation 4x - 5 = 4x + 10 has no solution because subtracting 4x from both sides yields -5 = 10, which is a contradiction.
Explanation:The equation 4x - 5 = 4x + 10 cannot be solved for x in the usual way because attempting to isolate x on one side will result in a contradiction. If we subtract 4x from both sides of the equation, we get -5 = 10, which is not true for any value of x. Therefore, this equation has no solution.
Line k is the perpendicular bisector of (line)PQ. If line k intersects (line)PQ at point R, which of the following statements must be true?
check all that apply
A. Line k bisects PQ
B. PR is congruent to QR
C. Line k intersects PQ at a 90 angle
D. Point R is the midpoint of line k
E. Line k is parallel to PQ
Answer:
A. Line k bisects PQ
B. PR is congruent to QR
C. Line k intersects PQ at a 90 angle
Step-by-step explanation:
A perpendicular bisector of a line is a segment that cuts right in the middle a line, and that segment forms a 90º degree angle with the line. This means that the point where the segment cuts the line would be exactly the half, making both resultant segments on the line congruent. So the options that are correct are ABC.
Over what interval of time in minutes was the jogger heart rate changing at the constant rate
We have a graph of the heart rate vs time.
We want to find on what interval the heart rate increases with a constant rate.
That interval is 3min ≤ t ≤ 4 min
The general function that increases with a constant rate is the general linear function:
y = a*x + b
Where a is the slope and also defines the constant rate of change.
Then the interval where the jogger heart rate changes at a constant rate is the part where we have a linear function (not the horizontal line, there the heart rate does not change).
Then the interval where the heart rate changes with a constant rate is:
3min ≤ t ≤ 4 min
If you want to learn more, you can read:
https://brainly.com/question/21670190
if a 24-day single payment loan has a periodic interest rate of 8.4% what is the approximate APR of the loan?
A. 201.6%
B. 127.8%
C. 12.8%
D. 20.2%
Answer:
Option B, 127.8%
Step-by-step explanation:
If a 24-day single payment loan has a periodic interest rate of 8.4%.
First we divide 365 by 24 to make periods of 24 days in one year.
365 ÷ 24 = 15.21
periodic interest rate of 8.4%
then Annual Percentage Rate = 15.21 × 8.4 = 1 27.76 ≈ 127.8%
127.8% is the approximate APR of the loan.
There are 10 people in a room. if each person shakes hands with exactly 3 other people, what is the total number of handshakes?
Which complex number has a distance of √17 from the origin on the complex plane?
A;2 + 15i
B:17 + i
C:20 – 3i
D:4 – i
Answer:
The complex number 4-i has distance [tex]\sqrt{17}[/tex] from origin.
D is correct
Step-by-step explanation:
We are given the absolute value of complex plane.
If complex number is a+ib then absolute value [tex]\sqrt{a^2+b^2}[/tex]
We have to check the absolute value of each option and check which is equal to [tex]\sqrt{17}[/tex]
Option A: 2+15i
[tex]d=\sqrt{2^2+15^2}=\sqrt{4+225}=\sqrt{229}\neq \sqrt{17}[/tex]
Option B: 17+i
[tex]d=\sqrt{17^2+1^2}=\sqrt{289+1}=\sqrt{290}\neq \sqrt{17}[/tex]
Option C: 20-3i
[tex]d=\sqrt{20^2+3^2}=\sqrt{400+9}=\sqrt{409}\neq \sqrt{17}[/tex]
Option D: 4-i
[tex]d=\sqrt{4^2+1^2}=\sqrt{16+1}=\sqrt{17}= \sqrt{17}[/tex]
Hence, The complex number 4-i has distance [tex]\sqrt{17}[/tex] from origin.
8/3 , 2.28, 10/12 , 0.199 what number in the list above has the greatest value?
Answer:
[tex]\frac{8}{3}[/tex] is the greatest value.
Step-by-step explanation:
The given numbers are [tex]\frac{8}{3}[/tex], 2.28, [tex]\frac{10}{12}[/tex], 0.199
In this question we have to find out greatest value.
So, first we convert all the values in decimals.
To convert [tex]\frac{8}{3}[/tex] in decimal form, we divide 8 by 3. The answer would be 2.67
2.28
[tex]\frac{10}{12}[/tex] = 0.83
0.199
Now we arrange these numbers in the increasing order.
0.199 < 0.83 < 2.28 < 2.67
So the greatest number is 2.67 that is [tex]\frac{8}{3}[/tex].
Could someone show me the work for 1/2 divided by 2/3 x 3/4
Find the 5th term in the expansion of (x – 3y)8
if 5(3x-7)=20 then what is 6x-8
Examine the graph at right. Then in a sentence suggest why the graph rises at 11:00am and drops at 1:15pm
A science experiment begins with a metal at −100° Celsius. The following function describes the temperature change per minute: f(x) = 89x − 100°. How will the graph of this function change if the metal is at 25° at the start of the experiment?
Answer:
A
Step-by-step explanation:
Jacobysontop!
If you had 5 green marbles and 8 red marbles, what's the probability that you'll pull out a marble that is green?
5+8 = 13 total marbles
5 are green
so you would have a 5/13 probability of picking a green one
The formula v = (radical)64h can be used to find the velocity v in feet per second of an object that has fallen h feet. Find the velocity of an object that has fallen 23 feet. Round your answer to the nearest hundredth.
A ) 184 feet per second
B ) 306.93 feet per second
C ) 38.37 feet per second
D ) 736 feet per second
Answer:
The answer is the option C
[tex]V=38.37\ ft/sec[/tex]
Step-by-step explanation:
we have that
[tex]V=\sqrt{64h}[/tex]
In this problem we have
[tex]h=23\ ft[/tex]
Substitute in the formula and solve for V
[tex]V=\sqrt{64(23)}[/tex]
[tex]V=\sqrt{1,472}\ ft/sec[/tex]
[tex]V=38.37\ ft/sec[/tex]
PLEASE HELP!!!!!!!dgbdgdbhdndcn
Denise is a professional swimmer who trains, in part, by running. she would like to estimate the average number of miles she runs in each week. for a random sample of 20 weeks, the mean is = 17.5 miles with standard deviation s = 3.8 miles. find a 99% confidence interval for the population mean number of miles denise runs. use a graphing calculator for this one and not the t chart from the book.
Using a 99% confidence level and the given data, the confidence interval for Denise's average weekly running mileage can be calculated using the sample mean, standard deviation, and z-score for the confidence level.
Explanation:Denise, a professional swimmer, uses her running mileage as part of her training analysis. To estimate the population mean for the number of miles she runs weekly, we will calculate the 99% confidence interval using the sample mean and standard deviation from her 20 weeks of data. The formula for a confidence interval is:
CI = mean ± (z* × (s/sqrt(n)))
Where mean is the sample mean, z* is the z-score corresponding to the desired confidence level, s is the sample standard deviation, and n is the sample size.
The given data for Denise's running mileage is a mean (μ) of 17.5 miles and standard deviation (s) of 3.8 miles with a sample size (n) of 20 weeks. Since the sample size is greater than 30, we can use the z-distribution to approximate the t-distribution.
To find the appropriate z-score for a 99% confidence interval, we can use a graphing calculator or a z-table. The z-score for a 99% confidence level is approximately 2.576. Plugging the values into the confidence interval formula:
CI = 17.5 ± (2.576 × (3.8/sqrt(20)))
Calculating the margins of error and applying them to the sample mean, we will obtain the confidence interval for the average number of miles Denise runs in a week.
4xy - 9xy + -3xy Simplify the polynomial
If 5+3+2=151012, 9+2+4=183662, 8+6+3=482466, 5+4+5= 202504 , then 7+2+5= ?
a.141035
b.143510
c.143542
d.143524
Two numbers, 3 and a, have a geometric mean of 9. Find the value of a.
We generally report a measurement by recording all of the certain digits plus ______ uncertain digit(s).
We generally report a measurement by recording all of the certain digits plus one uncertain digit.
What are significant figures?In positional nomenclature, a number's real numbers are its dependable and essential digits for indicating how much of something there is.
If a measurement's result is expressed by a number with more digits than the measurement resolution permits, only those digits up to the measuring resolution's maximum are trustworthy, and only those digits could be significant figures.
Typically, we record all the confirmed digits of measurement together with one questionable digit.
To know more about significant figures:
https://brainly.com/question/29153641
#SPJ5
Anthony was tracking the increasing number of animals in the zoo. at 9
a.m., there were 56 animals. at 11
a.m., there were 60 animals. if anthony made the function f(x) = 2x − 38, what would the 2 represent? the number of animals at midnight the rate at which the number of animals was increasing the length of time he recorded for the total change in the number of animals
It’s a little surprising that this question didn’t come up earlier. Unfortunately, there’s no intuitive way to understand why “the energy of the rest mass of an object is equal to the rest mass times the speed of light squared” (E=MC2). A complete derivation/proof includes a fair chunk of math (in the second half of this post), a decent understanding of relativity, and (most important) experimental verification.
Answer:
2 would represent the rate at which the animals were increasing
Step-by-step explanation: This all comes back to the slope intercept form:
y = mx + b
2x is the slope, and the slope is the rate of which a point will increase or decrease.
Two spheres of the same density have a ratio of 4 to 9 in surface area. If the small sphere weighs 10 kg, what does the large sphere weigh?
An experiment consists of dealing 5 cards from a standard 52-card deck. what is the probability of being dealt aa 10, jack, queen, king, ace, all in the same suit
Which of the following statements is the converse of the statement "If each of two angles has a measure of 28 degrees, then the two angles are equal in measure"?
Answer:
If two angles are equal in measure then each of the two angles has a measure of 28 degrees.
Step-by-step explanation:
The converse of a statement is found by switching the hypothesis and conclusion of a conditional statement.
The hypothesis is the part that comes after "if" and the conclusion is the part that comes after "then."
This means the hypothesis is "each of two angles has a measure of 28 degrees" and the conclusion is "the two angles are equal in measure."
This gives us the converse "If two angles are equal in measure then each of the two angles has a measure of 28 degrees."
The lifetime of a supertough aaa battery is normally distributed with mean of 28.5 hours and standard deviation of 5.3 hours. for a battery selected at random, what is the probability that the lifetime will be 25 hours or less?
A quadratic equation is shown below:
9x2 − 16x + 60 = 0
Describe the solution(s) to the equation by just determining the radicand. Show your work.
: Solve 4x2 + 8x − 5 = 0 by using an appropriate method. Show the steps of your work, and explain why you chose the method used.
hello :
help :
the discriminat of each quadratic equation :
ax²+bx+c=0 ....(a ≠ 0) is :
Δ = b² -4ac
1 ) Δ > 0 the equation has two reals solutions : x =
(-b±√Δ)/2a
2 ) Δ = 0 : one solution : x = -b/2a
3 ) Δ < 0 : no reals solutions
Which equation is not a quadratic equation?
y = 3x2 + 2
y = 5x - 2
y = -x2
y = 5x2 - 2x + 7