Mathematics Middle School

100 AAA batteries were tested on a particular MP3 player. Suppose the battery has a mean lifetime of 31.7 hours, with a standard deviation of 2.9 hours. How long do we expect the majority of batteries to last?A. Between 2.9 and 31.7 hours
B. Between 28.8 and 31.7 hours
C. Between 31.7 and 34.6 hours
D. Between 28.8 and 34.6 hours

Answers

Answer 1

31.7 -2.9 = 28.8

31.7 + 2.9 = 34.6

 between 28.8 & 34.6 hours

D is the correct answer

Related Questions

square root of 16r raised to the 6

Answers

If you mean:  (√(16r)^6  that is the same as:

(16r)^(1/2)^6

relevant rule:  (a^b)^c=a^(b*c), in this case

(16r)^(6*1/2)

(16r)^3

4096r^3

Answer:

4r^3

Step-by-step explanation:

The trick is to look for squared value and then to take them outside the square root but not in squared form.

A ball is thrown straight down from the top of a 499-foot building with an initial velocity of -29 feet per second. Use the position function below for free-falling objects.

Answers

position equation s(t) = -16t^2 + vo t + so vo = -30 so= 449 first determine the position after it has fallen 376 ft which would be 449- 376 then determine the time at the at that position once you've determined the time use the velocity equation or find the derivative of the position equation and substitute the time determined to find the velocity after it has fallen 376 ft

What is the value of the expression if z=27 7/9z-18+1/3z

Answers

The answer for this question would be: 4/81.

Answer:

The value of the expression is 12.

Step-by-step explanation:

Given :  Expression [tex]\frac{7}{9}z-18+\frac{1}{3}z[/tex] , where z=27

To find : The value of expression when z=27

Solution :

Given expression:

[tex]\frac{7}{9}z-18+\frac{1}{3}z[/tex]

Substitute value of z=27

[tex]=\frac{7}{9}(27)-18+\frac{1}{3}(27)[/tex]

[tex]=7\times 3-18+1\times 9[/tex]

[tex]=21-18+9[/tex]

[tex]=21-9[/tex]

[tex]=12[/tex]

Therefore, The value of the expression is 12.

Bradley needs to paint a logo made using two right triangles. The dimensions of the logo are shown below. What is the total area of the two triangles that need to be painted?

Two right triangles are attached along their longest side. The smaller triangle has height 6 cm and base 2 cm. The height of the larger triangle is 7 cm, and its base is 3 cm.

Answers

The formula to find area of a triangle is (base × height) ÷ 2

The area of the first triangle = (6 × 2) ÷ 2 = 6
The area of the second triangle = (7 × 3) = 10.5

Total area of the logo is 6+10.5 = 16.5 cm²

Which expression could be used to determine the product of –4 and 3 1/4?

Answers

Final answer:

To determine the product of -4 and 3 1/4, multiply the whole numbers and the fractions separately, and then add the results together.

Explanation:

The product of -4 and 3 1/4 can be determined by multiplying the whole number part, -4, by the whole number part of the mixed number, 3, and then multiplying the fraction part, 1/4, by the whole number part of the mixed number and adding the result to the previous product.

So, -4 × 3 = -12

and (-4) × (1/4) = -1

Therefore, the product of -4 and 3 1/4 is -12 - 1/4 = -12 1/4.

Final answer:

To find the product of -4 and 3 1/4, convert the mixed number to an improper fraction and then multiply.

Explanation:

The product of -4 and 3 1/4 can be found using the expression:

-4 x 3 1/4

To multiply a whole number by a mixed number, you can convert the mixed number into an improper fraction and then multiply:

-4 x 13/4

Multiplying whole numbers and fractions can be done by multiplying the numerators and denominators separately:

-4 x 13 = -52

4 x 1 = 4

The final answer is -52/4, which simplifies to -13.

What is the variance of the following data? If necessary, round your answer to two decimal places.
12, 13, 8, 13, 9, 11, 12, 9, 11
a)2.99
b)3.02
c)3
d)3.01

Answers

The formula of the variance, s^2, is

s^2 = sum [ value i - average]^2 for all the data i / (number of data)

Average = [12 + 13 + 8 + 13 + 9 + 11 + 12 + 9 + 11] / 9 = 98 / 9 = 10.889

data     value - average     (value - average)^2

12        12 - 10.889              1.2346

13        13 - 10.889              4.4568

8           8 - 10.889               8.3467

13         13 - 10.889             4.4568   

9           9 - 10.889               3.5679  

11         11 - 10.889              0.0123

12         12 - 10.889             1.2346

9           9 - 10.889               3.5679          

11         11 - 9.667              0.0123
                                         ------------
                      sum             26.8889

s^2 = 26.8889 / (n) = 26.8889 / (9) = 2.988 ≈ 2.99

Answer: 2.99

Write in standard form 60000+80000+10=

Answers

To solve this problem to standard form means adding all those numbers together. 
600,000+80,000= 680,000680,000+10= 680,010
680,010 is your answer

Every integer is a divisor of itself. A proper divisor of an integer means a positive divisor other than the integer itself. For example, the divisors of $8$ are $1,$ $2,$ $4,$ and $8,$ but the proper divisors of $8$ are just $1,$ $2,$ and $4$.

What is the smallest positive integer whose proper divisors add up to more than the integer itself?

Answers

the answer is 12
1x12 2x6 3x4
1+2+6+3+4=16
Final answer:

The smallest positive integer whose proper divisors add up to more than the integer itself is 12. Its proper divisors are 1, 2, 3, 4, and 6, which sum up to 16.

Explanation:

To understand this problem, we need to find the smallest positive integer whose proper divisors add up to a sum greater than the integer itself.

When we examine numbers, we find that the number 12 fits this description. The proper divisors of 12 are 1, 2, 3, 4, and 6. If we sum these up, 1 + 2 + 3 + 4 + 6, it equals 16, which is more than the number itself, 12.

Therefore, the smallest positive integer that meets this condition is 12.

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Solve 6x2 = 12x − 20.

Answers

If you are using the first X as a multiplication sign and the second as a variable the answer is 8/3 but if both are meant to be variables and the 2 is an exponent the answer is No real solutions
6x^2=12x-20  subtract 12x from both sides

6x^2-12x=-20  divide both sides by 6

x^2-2x=-10/3 halve the linear coefficient, square it, and add it to both sides, in this case 1

x^2-2x+1=3/3-10/3   now the left sides is a perfect square

(x-1)^2=-7/3  take the square root of both sides

x-1=±i√(7/3)  add 1 to both sides

x=1±i√(7/3)

*note that these are imaginary solutions, as the original equation is never true, or if you prefer, 6x^2-12x+20 is never equal to zero.


Television screens are measured along the diagonal. A certain 53-inch television is 45 inches wide. Which measurement represents the length of the hypotenuse?

Answers

the diagonal line. try visualizing the "sliced " into half. the diagonal line will be the side opposite the 90 degree angle, and being opposite of the right angle of the triangle proves that the hypotenuse of the is its diagonal line, which is 45-inch ((:

Answer:

Step-by-step explanation:

The right answer is 53in

Which unit of measurement would Guatemalans typically use to measure milk for a recipe? a) milliliters b) grams c) ounces d) gallons

Answers

Guatemalans would use milliliters because they use the metric system which is common throughout Latin America and which is basically easier to use than the Imperial system because it is all divisible by 10 whether it be millitres,litres,meters, kilometers etc.

Can you help me solve both

Answers

#6) 232/15 = 15.4666

sqrt(15.4666) = 3.932

3.932 * 3.932 x 15 = 231.91

 so edge is approximately 3.9 m


#7) 232/2 = 116

sqrt(116)=10.770

10.77 * 10.77 * 2 = 231.99

so edge is approximately 10.8 m


Marianne buys a house for 150,000 and the value of the house increases at a rate of 1.2% per year.How much will the house be worth in 10 years .Round to the nearest dollar.

Answers

To determine the value of the house in x number of years, we need to derive an equation that would relate the value of the house, the rate of increase and the number of years. If we calculate manually, we would do as follows:

V(1) = 150000 + 150000(0.012)
V(2) = 150000 + (150000 + 150000(0.012))(0.012)
V(3) =  .............

We need to do this up to 10 years. It would be a long and tedious process. We need to simplify the expression as follows:

We factor out the initial amount of the house and simplify further what is inside the parentheses. This would give us
V(x) = 150000 (1 + 0.012)^x 

Substitute 10 to x,
V(x) = 150000 (1 + 0.012)^x10
V(10) = 169003.77 

There are some chickens and goats on a farm. Given that the animals have a total of 50 heads and 140 legs, how many more more chicken than goats are there ?

Answers

Let the number of goats be 'x'.
Therefore, the number of chicken will be 50-x 
Total number of legs the goats will have= 4x (goats have 4 legs)
Total number of legs chickens will have= 2(50-x) (chickens have two legs).
4x + 2(50-x)=140
4x+100-2x=140
2x+100=140
2x=40
x=20.
There are 20 goats and 30 chickens.

In the rectangle below, the two quarter circles are congruent. Find the area of the shaded of the shaded region.

Answers

rectangle:
length = 12
width = 6
area of rectangle = length times width = 12 x 6 = 72

area of circle = pi r^2 = 3.14 (6)^2 = 113.1
1/2 circle = 113.1 / 2 = 56.55

the area of the shaded of the shaded region = 72 - 56.55 = 15.45

answer
15.45

One third of the bagels in a bakery are sesame bagels. There are 72 sesame bagels. Define a variable. Then write and slice an equation to find how many bagels there were in the bakery.

Answers

t=total bagels
s=sesame bagels

s x 3 = t

72 x 3 is 216.

there are 216 bagels in total, while 72 is just 1/3 of that

Simplify number 64. I am a little confused.

Answers

Because 9 has a whole number square root, simplify that first to get 3/root 5.
We don't want roots in the denominator so multiply the fraction by root 5/root 5 which is equal to 1.
The final answer is: 3 root 5/5

NEED ANSWER NOW! Worth LOTS OF POINTS!!!
In a proof of the Pythagorean theorem using similarity, what allows you to state that the triangles are similar in order to write the true proportions c/a=a/f and c/b=b/e ?

a) the geometric mean (altitude) theorem
b) the geometric mean (leg) theorem
c) the right triangle altitude theorem
d) the SSS theorem

Answers

In a right triangle, if we draw an altitude, from the vertex which contains the right angle, to its opposite side, the triangles at both sides of this altitude are congruent and hence congruent to the whole triangle.

The above is called the Right angle altitude theorem.

In PYthagorean theorem, we use the above theorem to prove the proportionate values are equal.

Answer:

It is C

Step-by-step explanation:


Solve the system of equations.
13x+2y=1
5x-2y=-19

Answers

18x = -18
x = -1
13(-1) + 2y = 1
y = 7 
(-1,7)
18x=-18
x=-1
then find y

Give an example of a polynomial where the ends are both facing downwards.

Answers

A polynomial where the ends are facing downwards is an even-degree polynomial with a negative leading coefficient.

An example for this is : f(x) = -x^2
where the degree is even (2) and the leading coefficient is negative (-1).
When graphing this function, you'll find both ends pointing downwards.

Chase answers 3/4 of his math questions correctly. There were 40 questions on the test.

a. How many did he get right?

b. How many did he miss?

Answers

Since there were 40 questions on a math quiz and he got 3/4 correct he got 30 correct and 10 incorrect.
A simple way to solve this is to add a zero to the end of each number in the fraction since there is 40 questions so it goes from 3/4 correct to 30/40 correct.
Hope this helps!!
Final answer:

Chase answered 30 questions correctly and missed 10 questions.

Explanation:

To find the number of questions Chase got right, multiply the fraction of questions answered correctly (3/4) by the total number of questions (40):

Number of questions answered correctly = (3/4) * 40 = 30

To find the number of questions Chase missed, subtract the number of questions he got right from the total number of questions:

Number of questions missed = 40 - 30 = 10

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The value of 34 + 6 ⋅ 5 = ___.

Answers

the answer is 64 because you have the multiply before you add
34+6×5=

multiply

34+30=

add

64

Write in Expanded form

Answers

(7x100,000)+(8x10,000)+(6x1,000)+(3x100)+(0x10)+(0x1)

Find all residues (A) such that (A) is its own inverse modulo 317.

Simpler version: Find all numbers (A) that equal its own inverse modulo 317

Answers

To solve for the value of the residues A, we can use the formula:

A^2 = 1                 (mod prime)

This is only true for prime numbers. The given number which is 317 is a prime number therefore the values of the residues A are:

A = + 1, - 1

Since I believe the problem specifically states for the list of positive integers only and less than 317, a value of A = - 1 is therefore not valid. However, a value of – 1 in this case would simply be equal to:

317 – 1 = 316

 

Therefore the residue values A are 1 and 316.

Ricky made 86 phone calls in 3 months. In the first month she made 21 calls, and in the second month she made 19 calls. How many calls did she make in the third month? 21 40 46 65

Answers

The answer is 46, if you add the amount of calls made in the first two months, then subtract it from the total calls made, in other word. 19+21=40 then go 86-40=46 then you have your answer
Ricky made 46 calls in the third month

Work:
19+21+40, and 86-40 =46

What is Perfect squares?

Answers

A perfect square is a number that can be expressed as the product of two equal integers.
the product of a rational number multiplied by itself 

Which number makes this sentence true?
21:30=x:50

A. X=30
B. X=32
C. X=35
D. X=41

Answers

the answer is a) x=30

Which set of steps shows the solution to the equation 2y = −8?
A) y = −8 − 2; y = 6
B) y = −8 ÷ (−2); y = 4
C)y = −8 ÷ 2; y = −4
D) y = −8 − (−2); y = −6

Answers

C is the correct answer.

please vote my answer brainliest. thanks!

C is correct answered first give me brainliest plus 5 star rating.

I've got two of these kinds of problems and no clue how to do them, help please!

Answers

Hello,

[tex]3x^3+2x^2-3x-2=0\\ 3x^3-3x+2x^2-2=0\\ 3x(x^2-1)+2(x^2-1)=0\\ (x^2-1)(3x+2)=0\\ (x-1)(x+1)(3x+2)=0\\ Sol=\{- \dfrac{2}{3}, -1,1 \} [/tex]
Doesn't X equal 0 because anything times 0 equals 0

How would I set this up?

(It's suppose to be a transformation.)

Answers

find the location of the points, multiply the y by 1/3

 draw the new triangle using the new points you calculated.

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