the average time of each runner is 12.36
Answer:
12.36 seconds
Step-by-step explanation:
Total time = 49.44 seconds
Students = 4
Average = 49.44/4 = 12.36 seconds
Answered by GAUTHMATH
Suppose that 25% of people own dogs If you pick three people at random, what
is the probability that they all three own a dog? (Let me add that we don’t know the
populations size so calculate the probability as if the population is infinite.)
Answer:
1/64
Step-by-step explanation:
25% own a dog, so picking one person has a probability of 1/4 (0.25) for that person to own a dog.
picking 3 people means combining (multiplying) the probabilities of the non-overlapping and non-depending events.
picking the third person has 1/4 chance of owning a dog (as the population is "infinite") combined with the chance that also the second pick owned a dog, which has to be combined with the chance of the first pick owning a dog.
so,
1/4 × 1/4 × 1/4 = 1/4³ = 1/64 = 0.015625
Instructions: State what additional information is required in order
to know that the triangles in the image below are congruent for the
reason given
Reasory. AAS Postulate
Step-by-step explanation:
AAS means angle angle side. so, we need 2 angles and 1 side.
the diagram shows us 1 angle in each triangle to be equal or congruent (C and G).
it also shows us implicitly, that the side AB is shared and is therefore truly the same for each triangle.
that means we need one more angle. either the one at A or the one at B. you pick.
An ice cream truck started the day with 454545 ice cream sandwiches. During a stop at a busy park they sold sss ice cream sandwiches. After the stop, the truck had 212121 ice cream sandwiches remaining.
Write an equation to describe this situation.
How many ice cream sandwiches did the truck sell at the park?
Answer:
45- s= 21
s= 45- 21
=24
so the answer is 24
A telephone service representative believes that the proportion of customers completely satisfied with their local telephone service is different between the South and the Midwest. The representative's belief is based on the results of a survey. The survey included a random sample of 1300 southern residents and 1380 midwestern residents. 39% of the southern residents and 50% of the midwestern residents reported that they were completely satisfied with their local telephone service. Find the 80% confidence interval for the difference in two proportions. Step 1 of 3 : Find the point estimate that should be used in constructing the confidence interval
Answer:
The point estimate that should be used in constructing the confidence interval is 0.11.
The 80% confidence interval for the difference in two proportions is (0.0856, 0.1344).
Step-by-step explanation:
Before building the confidence interval, we need to understand the central limit theorem and subtraction of normal variables.
Central Limit Theorem
The Central Limit Theorem establishes that, for a normally distributed random variable X, with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the sampling distribution of the sample means with size n can be approximated to a normal distribution with mean [tex]\mu[/tex] and standard deviation [tex]s = \frac{\sigma}{\sqrt{n}}[/tex].
For a skewed variable, the Central Limit Theorem can also be applied, as long as n is at least 30.
For a proportion p in a sample of size n, the sampling distribution of the sample proportion will be approximately normal with mean [tex]\mu = p[/tex] and standard deviation [tex]s = \sqrt{\frac{p(1-p)}{n}}[/tex]
Subtraction between normal variables:
When two normal variables are subtracted, the mean is the difference of the means, while the standard deviation is the square root of the sum of the variances.
Midwest:
50% of 1380, so:
[tex]p_M = 0.5[/tex]
[tex]s_M = \sqrt{\frac{0.5*0.5}{1380}} = 0.0135[/tex]
South:
39% of 1300, so:
[tex]p_S = 0.39[/tex]
[tex]s_S = \sqrt{\frac{0.39*0.61}{1300}} = 0.0135[/tex]
Distribution of the difference:
[tex]p = p_M - p_S = 0.5 - 0.39 = 0.11[/tex]
So the point estimate that should be used in constructing the confidence interval is 0.11.
[tex]s = \sqrt{s_M^2+s_S^2} = \sqrt{0.0135^2+0.0135^2} = 0.0191[/tex]
Confidence interval:
[tex]p \pm zs[/tex]
In which
z is the z-score that has a p-value of [tex]1 - \frac{\alpha}{2}[/tex].
80% confidence level
So [tex]\alpha = 0.2[/tex], z is the value of Z that has a p-value of [tex]1 - \frac{0.2}{2} = 0.9[/tex], so [tex]Z = 1.28[/tex].
The lower bound of the interval is:
[tex]p - zs = 0.11 - 1.28*0.0191 = 0.0856[/tex]
The upper bound of the interval is:
[tex]p + zs = 0.11 + 1.28*0.0191 = 0.1344[/tex]
The 80% confidence interval for the difference in two proportions is (0.0856, 0.1344).
What constant acceleration is required to increase the speed of a car from 30 miyh to 50 miyh in 5 seconds?
Answer:
The acceleration is 1.8 m/s^2.
Step-by-step explanation:
initial velocity, u = 30 mph = 13.4 m/s
Final velocity, v = 50 mph = 22.4 m/s
time, t = 5 s
Let the acceleration is a.
Use first equation of motion
v = u + at
22.4 = 13.4 + 5 a
a = 1.8 m/s^2
evaluate (-1)^6-4^0+(3/7)^0
Answer:
The answer is 1
.............
please mark this answer as brainlist
f(x) = 1 + 9. Find f '(x) and its domain.
A. f-1 (z) = (x – 9)?: x2 9
B. f-1(x) = (x – 9)?; x20
c. f-1 (2) = x2 – 9;x2 9
D. f-1 (x) = x2 – 9; x2 0
Answer:
B
Step-by-step explanation:
f(x) = sqrt(x) + 9
f(x) - 9=sqrt(x)
f^(-1)(x)=(x-9)^2 and it's domain is greater than 0
Question for the kids orrr?
Answer:
B. 18 sq in.
Step-by-step explanation:
Surface area of the triangular pyramid excluding the base = area of the three triangular faces = 3(½ × base × height)
Where,
base = 3 inches
height = ED = 4 inches
Plug in the known values into the equation
Surface area of the triangular pyramid excluding the base = 3(½ × 3 × 4)
= 3(3 × 2)
= 3(6)
= 18 sq in.
Which line is parallel to y = -2x + 8
Answer:
y=-2x-7
Step-by-step explanation:
after putting the choices with the question in a graph I found that that ones stays in a line with the question
Brainliest please!!
Which best describes the relationship between the lines with equations 2x – 9y = 1 and x + 8y = 6?
A. perpendicular
B. neither perpendicular nor parallel
C. parallel
D. same line
9514 1404 393
Answer:
B. neither perpendicular nor parallel
Step-by-step explanation:
If the lines were perpendicular, the coefficients would be swapped and one negated. (You would have 8x -y = c, or 9x +2y = c in the system.)
If the lines were parallel, the coefficients in the two equations would only differ by a common factor. (Both equations would reduce to 2x -9y = c, or x +8y = c.)
The lines are not the same line (coefficients are different).
So, the only reasonable description is ...
neither perpendicular nor parallel
Compare the functions shown below:
f(x) = 7x + 3 g(x) tangent function with y intercept at 0, 2 h(x) = 2 sin(3x + π) − 1
Mark is investing $8,000 in an account paying 5.5% interest compounded daily. What will Mark's account balance be in 6 years?
Picture is the answer
Ed decides to include more fruit in his diet. He goes to the grocery store over the weekend and buys 6 apples, 6 oranges, and 6 avocados. The total cost is $19.50.
Ed finishes the apples very quickly, and has some leftover avocado. The following weekend he buys 12 apples, 2 oranges, and 1 avocado. This time he pays just $9.50.
The following week, Ed reads an article on the benefits of avocado, so over the weekend he buys 5 avocados along with 2 apples and 4 oranges. His total this time is $14.
Assume that Ed pays a unit price rather than a price per pound for the apples, oranges, and avocados.
9514 1404 393
Answer:
apples: $0.50 eaoranges: $0.75 eaavocados: $2.00 eaStep-by-step explanation:
Let a, o, v represent the prices of one each of apples, oranges, and avocados, respectively. Then the equations describing the purchases can be written ...
6a +6o +6v = 19.50
12a +2o +1v = 9.50
2a +4o +5v = 14.00
__
Dividing the first equation by 6 makes it ...
a +o +v = 3.25
Subtracting this from the second equation gives ...
(12a +2o +v) -(a +o +v) = (9.50) -(3.25)
11a +o = 6.25
Subtracting the third equation from 5 times the reduced first equation gives ...
5(a +o +v) -(2a +4o +5v) = 5(3.25) -(14.00)
3a +o = 2.25
The difference of these last two equations is ...
(11a +o) -(3a +o) = (6.25) -(2.25)
8a = 4.00
a = 0.50
Then the other values are ...
o = 2.25 -3(a) = 0.75
v = 3.25 -a -o = 2.00
The unit prices are:
apples -- $0.50
oranges -- $0.75
avocados -- $2.00
_____
Additional comment
Most graphing or scientific calculators will solve systems of equations like these. Using an appropriate tool, it takes less time to find the solution than to read this one.
Note that the last purchase description in the problem statement has the items in a different order than in the first two descriptions. Care must be taken to make sure the correct equations are written.
Charity is planting trees along her driveway, and she has 6 pine trees and 6 willows to plant in one row. What is the probability that she randomly plants the trees so that all 6 pine trees are next to each other and all 6 willows are next to each other
Answer:
0.0022 = 0.22% probability that she randomly plants the trees so that all 6 pine trees are next to each other and all 6 willows are next to each other.
Step-by-step explanation:
A probability is the number of desired outcomes divided by the number of total outcomes.
In this question, the elements are arranged, so we have to use the arrangements formula.
Arrangements formula:
The number of possible arrangements of n elements is:
[tex]A_{n} = n![/tex]
Desired outcomes:
Pine trees(6!) then the willows(6!) or
Willows(6!) then the pine trees(6!). So
[tex]D = 2*6!*6! = 1036800 [/tex]
Total outcomes:
12 trees, so:
[tex]T = 12! = 479001600 [/tex]
What is the probability that she randomly plants the trees so that all 6 pine trees are next to each other and all 6 willows are next to each other?
[tex]p = \frac{D}{T} = \frac{1036800 }{479001600 } = 0.0022[/tex]
0.0022 = 0.22% probability that she randomly plants the trees so that all 6 pine trees are next to each other and all 6 willows are next to each other.
What is the order of rotational symmetry for the figure?
A. 3
B. 2
C. 4 or more
D. 1
9514 1404 393
Answer:
C. 4 or more
Step-by-step explanation:
Rotating the figure in increments of 90° will give the same figure. There are 4 such rotations in a full turn. The order of rotational symmetry is 4.
The product of two consecutive even integers is 10 less than 5 times their sum. Find the two integers. Answer in
the form of paired points with the lowest of the two integers first.
or
Answer:
(0,2) and (8,10)
Step-by-step explanation:
Let the smaller integer be 2n. The larger will be 2x+2.
ATQ. 2n(2n+2)+10=5(4n+2). Solving it, we get 2n=0 or 2n=8. The pairs are (0,2) and (8,10)
A building 51 feet tall casts a shadow 48 feet long. Simultaneously, a nearby statue casts a shadow of 16 feet. How tall is the statue? Choose an answer
Answer: 17 feet
Step-by-step explanation:
51/48 = x/16
(51)(16)/48
The statute is 17 feet tall.
What are the similar triangles?Similar triangles are the triangles that have the same shape, but different sizes. The corresponding angles are congruent and the sides are in proportion.
What is the ratio of any two corresponding sides of similar triangles?The ratio of any corresponding sides in two equiangular triangles is always the same.
Let's visualize the situation according to the given question.
AB is the building ,whose height is 51f
BC is the shadow of the building AB, whose length is 48ft.
QR is the shadow of the tower statue, whose length is 16feet.
Let the height of the statue PR be h feet.
In triangle ACB and triangle PRQ
∠ACB = ∠PRQ = 90 degrees
( the objects and shadows are perpendicular to each other)
∠BAC = ∠QPR
( sunray falls on the pole and tower at the same angle, at the same time )
⇒ΔACB similar to ΔPRQ ( AA criterion)
Therefore, the ratio of any two corresponding sides in equiangular triangles is always same.
⇒ AC/CB = PR/RQ
⇒[tex]\frac{51}{48} =\frac{h}{16}[/tex]
⇒ h = [tex]\frac{(51)(16)}{48}[/tex]
⇒ h = 17 feet.
Hence, the statute is 17 feet tall.
Learn more about the similar triangle here:
brainly.com/question/25882965
#SPJ2
if my savings of $x grows 10 percent each year, how much will i have in 2 years?
Answer:
$240
Step-by-step explanation:
A year has 12 month in it so lets multiply the 10 by 12 which is $120,Mean a year is $120 so 2years will be $120×2 which is $240
Answer:
x+1/5x
Step-by-step explanation:
Because the eqaution would be x+10%=x+1/10+10%=1/5+x
Then the equation equals x+1/5
Jenny bought scrapbooking supplies for $156.50. She paid $10.17 in sales tax. What was the sales tax rate on the supplies? If necessary, round your answer to the nearest tenth.
Answer:
6.5%
Step-by-step explanation:
sales price x sales tax rate = sales tax
156.50 x sales tax rate = 10.17
sales tax rate = 10.17/156.50
sales tax rate = .065 or 6.5%
In a sociology class there are 14 men and 10 women. 3 students are randomly selected to present a topic. What is the probability that at least 1 of the 3 students selected is female? Express your answer as a fraction or a decimal number rounded to four decimal places.
Answer:
0.8015
Step-by-step explanation:
Hope I'm correct lol
Let S be a set of linearly dependent vectors in Rn. Select the best statement. A. The set S could, but does not have to, span Rn. B. The set S spans Rn, as long as no vector in S is a scalar multiple of another vector in the set. C. The set S cannot span Rn. D. The set S must span Rn. E. The set S does not span Rn if some vector in S is a scalar multiple of another vector in the set. F. The set S spans Rn, as long as it does not include the zero vector. G. none of the above
Answer:
The set S could, but does not have to, span Rn ( A )
Step-by-step explanation:
Assume S is a set of linearly dependent vectors in Rn
The best statement from the options is ; The set S could, but does not have to, span Rn
This is because S could span Rn ( as stated in option c ) but will not necessary span Rn ( as seen in option D )
rút gọn :
(x+2)^2+(3-x)^2= ?
Step-by-step explanation:
=x^2+2x+4+9-6x+x^2
=2x^2-4x+13
Marnie just finished setting herself up at a cozy spot at the airport. Her laptop is ready, phone within reach, and her papers are organized, but now, she's hungry. What should she do? a) Take her phone and laptop with her to get something to eat b) Leave her stuff, but get a snack really quickly O c) Put her coat over her laptop to hide it and go get a snack O d) Ask the person next to her to watch her stuff
Answer:
a) someone will steal her stuff in any other situation even if a stranger watches it
Simplify the following expression:
(15b^5)^2
—————-
(5b^2)^3
Answer:
5x
Step-by-step explanation:
(75b x)x×2
---------------
(10b x)×3
=75b x×x×2
-----------------
10b x×3
=25x
-------
5
=5x
An auto transport truck holds cars. A car dealer plans to bring in new cars in June and July. If an auto transport truck is filled for each delivery, except for the last one, how many full truckloads are needed and how many cars will be in the last truck?
Answer:
95 truckloads
Last truck = 10 cars
Step-by-step explanation:
Capacity of auto truck = 12 cars
Total number of cars to be brought in = 1150
The number of truckloads required :
Total number of cars to be brought in / capacity of auto truck
Number of truckloads = 1150 / 12 = 95.83333
This means that the number of full truckloads required will be, the whole number = 95
The last truck won't be full and will contain :
1150 - (95 * 12)
1150 - 1140
= 10 cars
which of the following is a polynomial?
A. 15x^4
B. 6x^2/x
C. 4x^2+9x+12
D. 3- √2x
Answer:
C. 4x^2 + 9x + 12
Step-by-step explanation:
4x^2 + 9x + 12 is a polynomial.
Answer:
the answer is c
Step-by-step explanation:
A university is interested in promoting graduates of its honors program by establishing that the mean GPA of these graduates exceeds 5.1. A sample of 33 honors students is taken and is found to have a mean GPA equal to 5.2. The population standard deviation is assumed to equal 0.40. The parameter to be tested is ___________________________.
Answer:
B. The mean GPA of the university honors students
Step-by-step explanation:
Parameter in statistical parlance simply refers to numerical characteristics obtijed from the population dataset or observations. The population itself refers to all observations belonging to a particular or specific experiment or research. Here, the population is the all students belonging to the university's honors programme. The measured characteristic is the mean of the student's GPA. THEREFORE, the parameter will be the mean GPA of the honors student.
The ratio of the number of boys to that of girls in a school is 4:3. If the number of girls in the school is 162, find the number of boys in it. Then find the ratio of the number of girls to the total number of students in the school.
Answer:
total number of boys in skool is 216
And
ratio of girls to boys is a 3:4
Step-by-step explanation:
let total no. of boys be X
ACCORDING TO QUESTION
ratio of boys to girls = 4:3
total number of girls = 162
now
4/3=X/162
or, 4×162= 3x
or, 4×162/3= X
hence
X = 216
therefore total number of boys is 216
and
ratio of girls to boys is =162/216
=3/4
=3:4
Suppose your Unit Quiz grades have been: 85%, 80%, 96%, 72%, 78%, 85% and 92%
a) What is your average/mean score?
b) What is the median score?
c) What is the mode score?
d) Why is the mean lower than the median?
e) What will your mean be if you get a perfect score of 100% on your next quiz?
Answer:
mean: 84
median: 85
mode: 85
explainations for d and e below.
Step-by-step explanation:
mean:
(85+80+96+72+78+85+92)/7 = 544/7 = 84
median:
sort them in order from least to greatest first
72, 78, 80, 85, 85, 92, 96
find the middle number in that order, that's your median. in this case, it's 85.
mode:
number that appears the most in the order; the frequency. in this case as well, it's also 85.
answer for d:
the reason why the mean is lower than the median is because of the fact we were figuring out the average and had to divide, unlike the median where it's just the middle of the order we have.
answer for e:
(85+80+96+72+78+85+92+100)/8 = 644/8 = 80.5%
p.s: please subscribe to #gauthmath# sub reddit if you can for more help.
Independent simple random samples are selected to test the difference between the means of two populations whose standard deviations are not known. We are unwilling to assume that the population variances are equal. The sample sizes are n1 = 25 and n2 = 35. The correct distribution to use is the:
1) t distribution with 59 degrees of freedom.
2) t distribution with 58 degrees of freedom.
3) t distribution with 61 degrees of freedom.
4) t distribution with 60 degrees of freedom.
Answer:
2) t distribution with 58 degrees of freedom.
Step-by-step explanation:
Population standard deviations not known:
This means that the t-distribution is used to solve this question.
The sample sizes are n1 = 25 and n2 = 35.
The number of degrees of freedom is the sum of the sample sizes subtracted by the number of samples, in this case 2. So
25 + 35 - 2 = 58 df.
Thus the correct answer is given by option 2.
