The table shows some information about the lifetimes, t, in hours, of some lightbulbs.
Frequency
Lifetime
25 47
50 < t ≤ 100
86
100 45
150 < t ≤ 200
36
200 0
250 37
300 < t ≤ 350
50
Estimate the mean lifetime of a bulb.
Give your answer rounded to 2 DP.
hours

Answers

Answer 1

The estimated mean lifetime of a bulb of 154.69

How to estimate the mean lifetime of a bulb?

The table is given as:

Lifetime                Frequency

25 < t ≤ 50             47

50 < t ≤ 100            86

100 < t ≤ 150          45

150 < t ≤ 200         36

200 < t ≤ 250        0

250 < t ≤ 300       37

300 < t ≤ 350      50

Calculate the midpoint using:

x = (Lower +Upper)/2

So, we have:

Lifetime                Frequency

37.5                        47

75                           86

125                        45

175                        36

225                        0

275                       37

325                      50

The mean value is calculated as:

[tex]\bar x = \frac{\sum fx}{\sum f}[/tex]

So, we have:

[tex]\bar x = \frac{37.5 * 47 + 75 * 86 + 125 * 45 + 175 * 36 + 225 * 0 + 275 * 37 + 325 * 50}{47 + 86 + 45 + 36 + 0 + 37 + 50}[/tex]

Evaluate

[tex]\bar x = \frac{46562.5}{301}[/tex]

Divide

[tex]\bar x = 154.69[/tex]

Hence, the estimated mean lifetime of a bulb of 154.69

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Related Questions

Write an equation in slope intercept form of the line that passes through the point (0,4) with slope 2

Answers

Answer:

y=2x+4

Step-by-step explanation:

Slope=m=2

From(0,4)

y intercept=b=4

Equation in slope intercept form

y=mx+by=2x+4

Please answer its iready press the image below.
30 points btw

Answers

Answer:

alternate exterior angles

Step-by-step explanation:

<3 i hope this helps! sorry if it doesnt :)

7x<5x-16

It’s an inequality question

Answers

Answer:

7x <5x-16

Step-by-step explanation:

7x-5x < 5x -16 -5x

The area A of a circle is the product of π and the radius r squared

i need written in a algebraic equation

Answers

Answer:

A=πr^2

Step-by-step explanation:

A=π*r^2

Where, A is area of circle

r is radius of circle

π is constant

.

Hope it's help and I think I have give brainleist answer

Answer:

πr^2

Step-by-step explanation:

it's just πr^2.

easy

For an experiment, Sandra needs 20 grams of a 26% solution of salt. She has two large bottles of salt water: one contains a 20% solution, and the other contains 35% solution. How much of each must she use to make the solution she needs?

Answers

The amount of grams that she must use to make the solution she needs are: 12 grams and 8 grams.

Amount of grams

x grams of 20% and 20-x grams of 35%

Hence:

0.20x+0.35(20-x)=0.26×20

0.20x-0.35x+7=5.2

Collect like terms

-0.15x=-1.80

Divide both side by -0.15x

x=-1.80/-0.15

x=12 grams of 20% or 2.4 grams pure

20-x= (20-12) =8 grams of 35% or 2.8 grams pure

Therefore the amount of grams that she must use to make the solution she needs are: 12 grams and 8 grams.

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Calculate the volume of a cube of length 8 m

Answers

Answer:

V =512 m^3

Step-by-step explanation:

The volume of a cube is given by

V = s^3 where s is the side length

V = 8^3

V =512 m^3

It’s should be 512m!!! Good luck

Drag the expressions to show the order of their quotients from least to greatest

Answers

Answer:

by solving the divisions

Step-by-step explanation:

8/9 ÷ 7/11 = 8/9 × 11/7 = 88/63 = 1.4019/12 ÷ 3/10 = 19/12 × 10/3 =190/36 = 5.2819/12 ÷ 1/15 = 19/12 × 15 = 285/12 = 23.75

8/9 ÷ 3/10 = 8/9 × 10/3 = 80/27 = 2.96.

now from the solutions you can get the least to greatest

1.40 , 2.96, 5.28 and 23.75

After getting answer in decimal form change it to fraction like how they set the question

chandra is constructing a weighted bookend for her shelf. it is a hollow rectangular prism, as shown, and she will fill it with sand to weigh it down

Answers

Since it is said to be a hollow rectangular prism,  she will fill it with sand to weigh it about (573 + 9/2) cubic inches.

What is the prism about?

Note that the volume is said to be:

V = L x B x H

316 in = 6 √2 x 2 √3

The answer is 573 while the other part of the prison is 9√2 cubic inches.

Therefore, option A is correct.

See full question below

Chandra is constructing a weighted bookend for her shelf. It is a hollow rectangular prism, as shown, and she will fill it with sand to weigh it

down

6 √(2  in

316 in

2 √3 in

What is the volume of the bookend?

(Hint: The volume of a rectangular prism is the product of its length width and height.)

OA (573 + 9/2) cubic inches

B. 36/12 cubic inches

C 108 cubic inches

D. 216 cubic inches

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A pilot scheduled to depart at 4:00 pm, but due to air traffic, her departure has been delayed by 10 minutes. Air traffic control approved a new flight plan that will allow her to arrive three times faster then she calculated in her original flight plan. Let x represent the time, in minutes, of her original flight. Create an equation that can be used to predict the number of minutes after 4:00 pm she will arrive at her destination.

A. Y = 1/3x + 10
B. Y = 3x + 10
C. Y = 1/3x - 10
D. Y = 3x - 10

Answers

Answer: Choice A

y = (1/3)x+10

=============================================================

Explanation:

x = number of minutes of the original flight

Because the pilot travels 3 times faster than before, it means she travels 1/3 of the original time. If she took x minutes on the original flight, then she will take (1/3)x minutes for the new faster flight.

Then add on the 10 minute delay to end up with (1/3)x+10

Use mathematical induction to prove

Answers

[tex]Prove\ that\ the\ assumption \is \true for\ n=1\\1^3=\frac{1^2(1+1)^2}{4}\\ 1=\frac{4}{4}=1\\[/tex]

Formula works when n=1

Assume the formula also works, when n=k.

Prove that the formula works, when n=k+1

[tex]1^3+2^3+3^3...+k^3+(k+1)^3=\frac{(k+1)^2(k+2)^2}{4} \\\frac{k^2(k+1)^2}{4}+(k+1)^3=\frac{(k+1)^2(k+2)^2}{4} \\\frac{k^2(k^2+2k+1)}{4}+(k+1)^3=\frac{(k^2+2k+1)(k^2+4k+4)}{4} \\\frac{k^4+2k^3+k^2}{4}+k^3+3k^2+3k+1=\frac{k^4+4k^3+4k^2+2k^3+8k^2+8k+k^2+4k+4}{4}\\\\\frac{k^4+2k^3+k^2}{4}+k^3+3k^2+3k+1=\frac{k^4+6k^3+13k^2+12k+4}{4}\\\frac{k^4+2k^3+k^2}{4}+\frac{4k^3+12k^2+12k+4}{4}=\frac{k^4+6k^3+13k^2+12k+4}{4}\\\frac{k^4+6k^3+13k^2+12k+4}{4}=\frac{k^4+6k^3+13k^2+12k+4}{4}\\[/tex]

Since the formula has been proven with n=1 and n=k+1, it is true. [tex]\square[/tex]

What is the ratio of the area of sector abc to the area of sector dbe? a. b. c. d. e.

Answers

The ratio of the area of sector abc to the area of sector dbe is 4/3

How to determine the ratio of the areas?

For sector abc, we have:

Angle = x

Radius  = 2r

For sector dbe, we have:

Angle = 3x

Radius = r

The area of a sector is:

[tex]Area =\frac{\theta}{360}* \pi r^2[/tex]

So, we have:

[tex]ABC =\frac{x}{360}* \pi (2r)^2[/tex]

Evaluate

[tex]ABC =\frac{x* \pi r^2}{90}[/tex]

For DBE, we have:

[tex]DBE =\frac{3x}{360}* \pi (r)^2[/tex]

Evaluate

[tex]DBE =\frac{x}{120}* \pi r^2[/tex]

The ratio of both areas is:

[tex]Ratio = \frac{x}{90}* \pi r^2 : \frac{x}{120}* \pi r^2[/tex]

Cancel out the common factors

[tex]Ratio = \frac{1}{90} : \frac{1}{120}[/tex]

Express as fraction

[tex]Ratio = \frac{120}{90}[/tex]

Divide

[tex]Ratio = \frac{4}{3}[/tex]

Hence, the ratio of the area of sector abc to the area of sector dbe is 4/3

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4/3

its the answer edmentum

Which number can each term of the equation be multiplied by to eliminate the decimals before solving? –m 0.02 2.1m = –1.45 – 4.81m

Answers

Answer:

Pretty certain it's 100



Which point is located at (3, -1)?



A. point A

B. point D

C. point E

D. point F

Answers

Answer:

i think its point D. So that means the answer is B. I think so because if the middle like going side to side is marked first then it must mean the positive is first and so it's point D

If the population of

an alien race doubles

every two minutes,

how long will it take

for the population to

grow from 1,000 to 32,000 ?

Answers

It would take 32 minutes.

1,000 * 32 = 32,000

It will take 32 minutes for the population to grow from 1,000 to 32,000.

What is the unitary method?

The unitary method is a method for solving a problem by the first value of a single unit and then finding the value by multiplying the single value.

If the population of an alien race doubles every two minutes,

1,000 x 32 = 32,000

Hence, It would take 32 minutes.

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Please help! Giving brainliest!

Answers

Answer:

P

Step-by-step explanation:

The middle is the middle of the angle ...point P

Consider triangle ABC. What is b?

Answers

b would equal 18.7
Explanation:

Determine the value of x. : A) B) 4 C) 4 D) 8

Answers

The hypotenuse is always the longest side of a triangle and seeing that it is 8, X has to be something smaller so X is likely 4.

Drag the correct value into each box on the number line.

Answers

To identify the value that goes in each box, we must perform the corresponding operation and calculate the final result.

How to perform a mathematical operation?

In mathematics there are procedures such as addition (+), subtraction (-), division (÷), and multiplication (×) to solve problems. These operations are the four basic operations of mathematics.

According to the above, what we must do is identify what operation we must perform with the given numbers and then identify the result and put it in the corresponding box.

Note: This question is missing because there is some information missing. Howeve i can answer it based on my general knowledge.

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A group of students measured the lengths of their shoes. The lengths are listed in the table. Use the table to locate the incorrect data in the line plot.

Answers

I think the incorrect data is the second x to the left.

I need help please question is in the image

Answers

im pretty sure that it’s 700

9. Latoya's mom makes her a birthday cake in the shape of an "L". Latoya loves frosting,
so her mom covers the entire outside of the cake in frosting, even the bottom of the
cake.
4 in
12 in
2 in
9 in
How much space does Latoya's mom cover in frosting?
inches²
8 in
4 in

Answers

Answer:

223

Step-by-step explanation:

find the area for each side.

This Stem-and-Leaf Plot shows the scores of 10 students on a recent math test.

Which statistic is most affected by the lowest score?

A. the mean
B. the median
C. the mode
D. the mean and the median

Answers

The statistic that is most affected by the lowest score is A. the mean

How to determine the most affected statistic?

The stem and leaf plot is missing from the question;

However, the question can be solved without it.

The lowest score on the stem and leaf plot is an outlier of the plot.

In statistics, outliers have huge effect on the mean of the dataset and they have little or no effect on the median and mode

This means that, the statistic that is most affected by the lowest score is A. the mean

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1. Use rectangle ABDC below for parts a through d.
15 cm
B
8 cm
C
(a) Calculate the length of each side of the dilated image using a scale factor of 3. Show your work!
(2 pts)
A'B' = |
B'D' =
I
(b) Does the scale factor of 3 create an enlargement or reduction? (1 pt)
(c) Calculate the length of each side of the dilated image using a scale factor of Show your workl
(2 pts)
A'B' =
B'D' =
(d) Does the scale factor of create an enlargement or reduction? (1 pt)

Answers

Answer:

see the attachment photo!

x+y=5
3x-y=7
solve this equation

Answers

The intercepts for x+y=5
X= (5,0)
Y= (0,5)
Slope is 3 and y intercept is (0,7)

Help will name brainliest

Answers

[tex]\text{For angle N,}\\\\PQ= \text{Perpendicular.}\\\\QN = \text{Hypotenuse.}\\\\\text{Now,}\\\\\sin N = \dfrac{\text{Perpendicular}}{\text{Hypotenuse}}\\\\\\~~~~~~~=\dfrac{QP}{QN}[/tex]

In circle O, ST is a diameter.

Circle O is shown. Line segment S T is a diameter. Line segments R O and U O are radii. Angles R O U and U O T are congruent. The measure of arc R S is (2 x + 8) degrees, the measure of arc R U is (3 x minus 14) degrees, and the measure of arc U T is (3 x minus 14) degrees.

What must be the value of x?

22.0
25.0
25.4
37.2

Answers

The value of x must be 25.0. The correct option is the second option-  25.0

Solving Linear equations

From the question, we are to determine the value of x

From the given diagram, we can write that

m ∠SOR + m ∠UOR + m ∠TOU = 180° (Sum of angles on a straight line)

∴ (2x +8)° + (3x - 14)° + (3x -14)° = 180°

2x° + 8° + 3x° -14° + 3x° -14° = 180°

Collect like terms

2x° + 3x° + 3x° + 8° - 14° -14° = 180°

8x° -20° = 180°

8x° = 180° + 20°

8x° = 200°

x = 200/8

x = 25.0

Hence, the value of x must be 25.0. The correct option is the second option-  25.0

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Answer:

25.0

Step-by-step explanation:

just took it

\

Find the exact length of side a.

Answers

The exact length of a which is equivalent to BC is 7units

Cosine rule

A triangle is a shape with 3 sides and angles. In order to determine the sides BC, we will use the cosine rule

c² = a² + b² - 2abcosC

Given the following parameters

b = 2

c = 5√3

theta = 30 degrees

Substitute

c² = 2² + (5√3)² - 2abcos30
c² = 4 + 75 - 2(2)(5√3)*√3/2

c² = 79 - 30
c² = 49
c = 7 units

Hence the exact length of a which is equivalent to BC is 7units

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Use inductive reasoning to find the 10th term in the sequence 5, 8, 11, 14, ...


34


32


50


17

Answers

Answer: 32

Step-by-step explanation: this is arithmetic sequence

general formula = a+(n-1)d

nth term = 5+(n-1)3

=5+3n-3

=2+3n

10th term = 2+3(10)

=32

Select the correct answer. if a coin is flipped 10 times, what is the probability that it will show all heads or all tails? a. b. c. d. e.

Answers

Answer:

Step-by-step explanation:

1/2 chance for 1

1/4 for 2

1/8 for 3

1/16 for 4

1/32 for 5

1/64 for 6

1/128 for 7

1/256 for 8

1/512 for 9

1/1024 for 10

What is the solution to
[tex] \sqrt{ - x} = \sqrt{x + 13} [/tex]

Answers

Answer: -6.5

Step-by-step explanation:

First, you take the values on both sides to the power of 2 to get:

-x = x + 13

Subtract x on both sides.

-2x = 13

Divide both sides by -2.

x = -6.5

Answer:

[tex]x=-\dfrac{13}2[/tex]

Step-by-step explanation:

[tex]~~~~~\sqrt{-x} = \sqrt{x+13}\\\\\implies -x= x+13~~~~~~~~~~~~~~~~;[\text{Square on both sides}]\\\\\implies -x -x = 13\\\\\implies -2x = 13\\\\\implies x = -\dfrac{13}2\\\\\text{Verify solution:}\\\\~~~~~~~\sqrt{-\left(- \dfrac{13} 2 \right)} = \sqrt{-\dfrac{13}2 +13}\\\\\\\implies \sqrt{\dfrac{13}2} = \sqrt{\dfrac{13}2}\\\\\text{Hence, the solution is}~ x=-\dfrac{13}2[/tex]

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