Answer:
2.25 seconds
Step-by-step explanation
[tex]d=16t^{2}[/tex]
[tex]d=81 feet\\t=?[/tex]
Because you know what distance equals you can plug it into the equation
[tex]81=16t^{2}[/tex]
From there you can solve by dividing the 16 over and then square rooting.
[tex]\frac{81}{16}=t^{2}[/tex]
[tex]5.0625=t^{2}[/tex]
You take the square-root to get rid of [tex]t^{2}[/tex]
[tex]\sqrt{5.0625} =\sqrt{t}^{2}[/tex]
[tex]t=2.25[/tex]
A marketing research company desires to know the mean consumption of milk per week among people over age 45. They believe that the milk consumption has a mean of 4.2 liters, and want to construct a 98% confidence interval with a maximum error of 0.08 liters. Assuming a standard deviation of 0.6 liters, what is the minimum number of people over age 45 they must include in their sample
Answer:
The minimum number of people over age 45 they must include in their sample is 305.
Step-by-step explanation:
We have that to find our [tex]\alpha[/tex] level, that is the subtraction of 1 by the confidence interval divided by 2. So:
[tex]\alpha = \frac{1 - 0.98}{2} = 0.01[/tex]
Now, we have to find z in the Ztable as such z has a pvalue of [tex]1 - \alpha[/tex].
That is z with a pvalue of [tex]1 - 0.01 = 0.99[/tex], so Z = 2.327.
Now, find the margin of error M as such
[tex]M = z\frac{\sigma}{\sqrt{n}}[/tex]
In which [tex]\sigma[/tex] is the standard deviation of the population and n is the size of the sample.
Standard deviation of 0.6 liters
This means that [tex]\sigma = 0.6[/tex]
What is the minimum number of people over age 45 they must include in their sample?
This is n for which M = 0.08. So
[tex]M = z\frac{\sigma}{\sqrt{n}}[/tex]
[tex]0.08 = 2.327\frac{0.6}{\sqrt{n}}[/tex]
[tex]0.08\sqrt{n} = 2.327*0.6[/tex]
[tex]\sqrt{n} = \frac{2.327*0.6}{0.08}[/tex]
[tex](\sqrt{n})^2 = (\frac{2.327*0.6}{0.08})^2[/tex]
[tex]n = 304.6[/tex]
Rounding up:
The minimum number of people over age 45 they must include in their sample is 305.
A 20-question multiple choice quiz has five choices for each question. Suppose that a student just guesses, hoping to get a high score. The teacher carries out a hypothesis test to determine whether the student was just guessing. The null hypothesis is p = 0.20, where p is the probability of a correct answer.
a. Which of the following describes the value of the z-test statistic that is likely to result? Explain your choice.
i. The z-test statistic will be close to 0.
ii. the z-test statistic will be far from 0.
b. Which of the following describes the p-value that is likely to result? Explain your choice.
i. The p-value will be small.
ii. The p-value will not be small.
Answer:
a) i. The z-test statistic will be close to 0, as the sample mean and the tested proportion are expected to be close values.
b) ii. The p-value will not be small, as the z-statistic is close to 0.
Step-by-step explanation:
The null hypothesis is p = 0.20
The teacher carries out a hypothesis test to determine whether the student was just guessing.
Test if the proportion is different from 0.2. So the alternate hypothesis is:
[tex]H_{a}: p \neq 0.2[/tex]
Five choices for each question, one of which is correct.
Probability of having a correct answer is [tex]X = \frac{1}{5} = 0.2[/tex]
The test statistic is:
[tex]z = \frac{X - \mu}{\frac{\sigma}{\sqrt{n}}}[/tex]
In which X is the sample mean, [tex]\mu[/tex] is the value tested at the null hypothesis, [tex]\sigma[/tex] is the standard deviation and n is the size of the sample.
a. Which of the following describes the value of the z-test statistic that is likely to result?
In this question, [tex]X = p = \mu[/tex], which meas that the numerator of the z-statistic will be close to 0, which means that the z-test statistic will be close to 0.
b. Which of the following describes the p-value that is likely to result?
pvalue is 2 multiplied by the pvalue of Z(if negative), or 1 subtracted by the pvalue of Z(if positive).
Since the value of Z is close to 0, either the pvalue of Z or 1 subtracted by the pvalue of Z is close to 0.5, and multiplied by 2 will be close to 1. So, as Z is close to 0, the pvalue will not be small.
A $45 pair of shoes is on sale for 20% off. How much money is saved?
Answer:
$9
Step-by-step explanation:
COMBINE ALL LIKES TERMS.
r+r+r+r
r+3r+2
Answer:
r+r+r+r=4r
r+3r+2=4r+2
Step-by-step explanation:
1. r+r+r+r
r+r+r+r
=(r+r)+(r+r) ⇔ Group two together
=2r+2r ⇔ Simplify
=4r
2. r+3r+2
r+3r+2
=4r+2
Hope this helps!! :)
Please let me know if you have any quesitons
Answer:
8r+2
Step-by-step explanation:
Will mark brainliest !! Easy math
Answer:
increase = 37.38 cm²
You'd like the first way because it took less effort and less chance of a miscalculation.
Step-by-step explanation:
first way:
(just work with the difference in height)
(0.7 x 8.7 x 2) + (0.7 x 18 x 2) = 37.38 cm²
second way:
old total lateral surface area = (31 x 8.7 x 2) + (31 x 18 x 2) = 1655.4
new total lateral surface area = (31.7 x 8.7 x 2) + (31.7 x 18 x 2) = 1692.78
increase = 1692.78 - 1655.4 = 37.38 cm²
Answer:37.38cm2
Step-by-step explanation:
Please help I’ll mark you as brainliest if correct!
Answer:
B
Step-by-step explanation:
brainliest?
Suppose y varies directly with x and inversely with z. If y = 14 when x = 7 and z = 3, what is x when y = 3 and z = 8? Use the step-by-step process you learned to solve this problem.
Step 1: Set up the correct type of variation equation.
y =
✔ kx/z
Step 2: Determine the constant of variation.
k =
Answer:
The constant of variation k is 6 and the value of x is 4.
Step-by-step explanation:
What is constant of variation?
The constant of variation is the number that relates two variables that are directly proportional or inversely proportional to one another.
What is direct variation?
A direct variation is a proportionality relationship in which two quantities follow a direct relationship.
What is inverse variation?
Inverse variation states when one variable increases then the other variable decreases.
Given,
y=14 when x=7 and z=3
The variation equation is,
y=kx/z
Inputting the values,
14=(k*7)/3
14*3=7*k
42=7k
k=6
When y=3, z=8 we will find x.
y=kx/z
3=6*x/8
3*8=6*x
x=24/6
x=4
Hence, the value is 4.
To know more about constant of variation, direct variation, inverse variation here
https://brainly.com/question/11733777
#SPJ2
A satellite system consists of 4 components and can function if at least 2of them are working. If each component independently works with probability 0.8, what is the probability the system will function?
Answer:
X follows binomial distribution with n=4, p=0.6, q= 0.4. To make the system function adequately, at least 2 components should work well.
Step-by-step explanation:
Hope this helps
Answer:
0.9728
Step-by-step explanation:
We have 2 options for the system to fail - no components work, or only one works.
The probability that no components work is:
[tex]0.2^4 = 0.0016[/tex]
The probability that one SPECIFIC component works and the others failed is:
[tex]0.2^3 \cdot 0.8 = 0.0064[/tex]
And because there's 4 components, the chance that EXACTLY ONE works but the others don't is:
[tex]4 \cdot 0.0064 = 0.0256[/tex]
So we sum the probabilities:
[tex]P_{failure} = 0.0016 + 0.0256 = 0.0272\\P_{works} = 1 - P_{failure} = 0.9728[/tex]
If I get 9 books for $36 of much does one cost
2 1/5 + 6 4/5 pls help
Answer:
2 1/5 + 6 4/5
= 2/5 + 24/5
= 26/5
= 5.2
Answer:
[tex]8\frac{5}{10}[/tex]
Step-by-step explanation:
[tex]2 + 6 = 8\\\frac{1}{5} + \frac{4}{5} = \frac{5}{10}[/tex]
Let me know if this helps!
Please helpppp meeee
It takes Paul 9 hours longer than Li Ming to paint a house. Working together they can do the job in 20 hours. How long would it take Li Ming, working alone, to paint the house ?
Li Ming can paint the whole house in 10 hours
Whisper is exercised twice a day.
The first time is for 30 minutes.
The second time is for 11 hours.
i. Write down the fraction of a day that Whisper is exercised.
Write your answer in its simplest form.
ii.
Write down the fraction of a day that she is not being exercised.
Answer:
I:23/48
ii 25/48
Step-by-step explanation:
30min=0.5hr
total time exercised: 11+0.5=11.5hr
Divided by total hours of a day:
11.5/24=115/240=23/48
ii:(48-23)/48
https://studio.code.org/projects/flappy/cYGc2S_X9-cgWtBUmJ5BJta5xku7iqyon0wzrKhC-Do
Answer:
so fun and amazing!
Step-by-step explanation:
Help,,,,,,,,,,,,,,,........
The mixed number 2 5/6 is equivalent to a fraction with a
denominator of 6.
What is the missing numerator in the equivalent
fraction?
Answer:
6 x 2 = 12 then add 5, answer is 17
Two intersecting segments form the diagonals of a quadrilateral. What additional information do you need to know about the diagonals to prove that a quadrilateral is a parallelogram
Answer:
B. They must bisect each other
Step-by-step explanation:
Found the answer on quizziz
Round 329,167 to the nearest hundred
Answer:
329,200
Step-by-step explanation:
Answer:
329,200
Step-by-step explanation:
what is the lateral area of the cone? 10 yd and 12.1 yd
Answer:
The lateral area will be "381 yd²". A further solution is provided below.
Step-by-step explanation:
The given values are:
Radius of cone,
r = 10 yd
Height of cone,
L = 12.1 yd
As we know,
The lateral surface area of cone is:
= [tex]\pi r L[/tex]
On substituting the values, we get
= [tex]\frac{22}{7}\times 10\times 12.1[/tex]
= [tex]\frac{22}{7}\times 121[/tex]
= [tex]380.28 \ yd^2[/tex]
0r,
= [tex]381 \ yd^2[/tex]
What is (14x^2– 27x+9) / (7x-3)?
A. 7x-3
B. 2x-3
C. -211x+9
D. 2x-33
Answer:
B. 2x - 3
Step-by-step explanation:
[tex] \rm \frac{ {14x}^{2} - 27x + 9}{7x - 3} [/tex]
[tex] \rm = \frac{ \cancel{(7x - 3)}(2x - 3)}{ \cancel{7x - 3}} [/tex]
[tex] \boxed{ \rm \bold{= 2x - 3}}[/tex]
Answer:
[tex]\tt{}2x - 3[/tex]
Step-by-step explanation:
[tex] \tt{} \frac{(14 {x}^{2} - 27x + 9) }{(7x - 3)} [/tex]
[tex] \tt{} \frac{14 {x}^{2} - 6x - 21x + 9 }{7x - 3} [/tex]
[tex]\tt{} \frac{2x \times (7x - 3) - 3(7x - 3)}{7x - 3 } [/tex]
[tex]\tt{}2x - 3[/tex]
A metal bar weighs 9.65 ounces. 78% of the bar is Gold. How many ounces of
Gold are in the bar? (round to the nearest thousandths)
Answer: 7.527 oz
Step-by-step explanation: 78%= 0.78
Mass of gold is 0.78 · 9.65 oz = 7.527 oz
IF YOU ANSWER ALL THESE QUESTIONS I WIL LGIVE YOU BRAINIEST AMD 40 POINTS COME UP WITH PROBLEMS THANKS
Answer:
WHY YOU ARE ALWAYS SAY THAT CAN YOU WHOLE QUESTION..
What is the value of 4+2 +6r – tr when t =
=
- 3 and r = 5?
Enter your answer in the box.
you first substitute your values t and r ...Use BODMAS method ...Your final answer must be 51
B
130 ft
10°
19°
A
D
This graph represents the height a baseball travels in t seconds.
How long is the height of the ball increasing?
0.5 seconds
1 second
2.4 seconds
30 seconds
blank plus 1/2 equals to 2/3
Answer:
1/6 + 1/2 = 2/3
Step-by-step explanation:
500 people are asked if they drink coffee.
9
10 say Yes.
20% of the people who say Yes drink at least three cups each day.
(b)
What fraction of the 500 people drink at least three cups of coffee each
day?
Give your answer in its simplest form.
Answer:
Step-by-step explanation:
2/10
All of number 3 plz and thank u!
Week 5 Test Taking skills, Page 2
Name
3
Rodrigo bought a sheet of shark stickers. He used 8 of the 32 stickers to decorate his science project about
sharks.
Shark Stickers
DO
How many shark stickers did Rodrigo use on his science project?
A
24
B
18
с
20
D
30
It’s number 3
Answer:
20
Step-by-step explanation:
5/8 of 32
5/8×32=20
remember of means multiply
HOPE THIS HELP YOU HAVE A NICE DAY OR NIGHT
HELP ASAP A factory makes car batteries. The probability that a battery is defective is is.
If 400 batteries are tested, about how many are expected to be defective?
A. 25
B. 40
C. 16
D. 375
375 is the ansewer wwrhttttttttttttttttttt
Answer:
25
Step-by-step explanation: