Alexey wrote '1*2*3*... 9 = 21' on the board, inserting a plus or minus signs in place of each little star. Sasha changed some of these signs to their opposites so that the result he got was 20. Prove that one of the boys made a mistake.​

Answers

Answer 1
someone answer the question on page btw ion kn the answer to this

Related Questions

Write each expression using exponents.
3/8 * 3/8 * 3/8=

Answers

Answer:

3/8^3

Step-by-step explanation:

the exponent is 3

Answer:

(3/8)^3

3^3 * 2^-9

Step-by-step explanation:

3/8 * 3/8 * 3/8 = (3/8)^3

= 3^3 * (1/8)^3 = 3^3 * (2^-3)^3 = 3^3 * 2^-9

someone please help with this!! 10 points available!!

The approximate volume is ___ cubic centimeters. Do not round your answer.

Use 3.14 for π.

Answers

Answer:

19329.84

Step-by-step explanation:

3.14×18 which is squared so it 324×19

3.14×324×19= answer

​HURRY PLEASE!!!!!! Boden's account has a principal of ​$300 and a simple interest rate of ​4.4%. Complete the number line. How much money will be in the account after 4​ years, assuming Boden does not add or take out any​ money?

Answers

Answer:

$66.00

Step-by-step explanation:

first we need multiply :D I will use the formula I =prt

principal= $500

rate=3.3%

time= 4 years

but we need to convert the percent, 3.3%, to a decimal

3.3%=0.033 or .033

now we multiply !

500 × 0.033 × 4 = 66 = $66.00

10 mins to submit please help FAST

Answers

Answer:

Step-by-step explanation:

I got 408.33. dont know how to help you out

The mean room temperature from Monday to Saturday is 25oC and the mean room temperature of Saturday and Sunday is 28oC. if the mean room temperature from Monday to Sunday is 26oC, find the room temperature on Saturday

Answers

Answer:

We can conclude that the room temperature on Saturday was 24°C

Step-by-step explanation:

For a set of N values:

{x₁, x₂, ..., xₙ}

The mean of the set is calculated as:

[tex]M = \frac{x_1 + x_2 + ... + x_n}{N}[/tex]

In this case, our set is the temperature of 7 days (so we have 7 elements)

{T₁, T₂, T₃, T₄, T₅, T₆, T₇}

Such that:

T₆ = temperature on Saturday

T₇ = temperature on Sunday.

We know that:

"The mean room temperature from Monday to Saturday is 25°C"

Then:

[tex]\frac{T_1 + T_2 + T_3 + T_4 + T_5 + T_6}{6} = 25 C[/tex]

"the mean room temperature of Saturday and Sunday is 28°C"

[tex]\frac{T_6 + T_7}{2} = 28C[/tex]

"The mean room temperature from Monday to Sunday is 26°C"

[tex]\frac{T_1 + T_2 + T_3 + T_4 + T_5 + T_6 + T_7}{7} = 26 C[/tex]

So we have 3 equations.

Let's rewrite:

T₁ + T₂ + T₃ + T₄ + T₅ = A

Then we can rewrite our equations as:

[tex]\frac{A+ T_6}{6} = 25 C[/tex]

[tex]\frac{T_6 + T_7}{2} = 28C[/tex]

[tex]\frac{A + T_6 + T_7}{7} = 26 C[/tex]

Removing the "Celcius" and multiplying in the 3 equations by the denominator on both sides, we get:

A + T₆ = 6*25

T₆ + T₇ = 2*28

A + T₆ + T₇ = 7*26

We now need to solve that system for T₆

The first step is to isolate one of the variables in one of the equations, (because we want to solve this for T₆ , let's not isolate that one). Let's isolate A in the first one:

A = 6*25 -  T₆

A = 150 -  T₆

Now we can replace this on the other two equations:

T₆ + T₇ = 2*28

(150 -  T₆ ) + T₆ + T₇ = 7*26

Now, let's isolate T₇  in the top equation to get:

T₇  = 2*28 - T₆

T₇  = 56 - T₆

Now we can replace this in the last equation to get:

(150 -  T₆ ) + T₆ + (56 - T₆)  = 7*26

Now, we can solve this for T₆

150 - T₆ + T₆ + 56 - T₆ = 182

-T₆ = 182 - 150 - 56

-T₆ = -24

T₆ = 24

We can conclude that the room temperature on Saturday was 24°C

what is the solution to 8t - 2 - 9t < 5?​

Answers

Answer:

t > -7

Step-by-step explanation:

8t - 2 - 9t < 5

Combine like terms

- 2 - t < 5

Add 2 to each side

-2-t+2 < 5+2

-t <7

Multiply each side by -1, remembering to flip the inequality

t > -7

The box-and-whisker plot shown displays the number of hours 20 student athletes spend exercising during the week.

Which number best describes the range of the data in the box-and-whisker plot?
A. 25
B. 15
C. 10

Answers

15 because 20-5 is 15

The number that best describes the range of the data in the box-and-whisker plot is 15.

What is the range?

A box plot is used to study the distribution and level of a set of scores the scores are distributed into 4 groups. Each group has a value of 25%. The box plot consists of two lines and a box. the two lines are known as whiskers. the whiskers represents the minimum and maximum values.

Range = maximum value - maximum value  

20 - 5  = 15

To learn more about box plots, please check: https://brainly.com/question/27215146

#SPJ2

Two odd numbers are selected at random from integers 11 through 22. Find the
probability that the two numbers are multiples of 3 after replacing first? JUST
SHOW MATH!*

Answers

I mean the answer is 34 sorry for the mistake

Probability  that the two numbers are multiples of 3 after replacing first

What is Probability?

It is a branch of mathematics that deals with the occurrence of a random event.

The odd integers from11 to 22 are

11,13,15,17,19,21

So there are 6 events

Out of these 6 numbers, 2 numbers (15,21) are multiples of 3.

One number out of these 2 numbers can be chosen in 2 ways.

Therefore, favourable number of elementary events = 2.

Required probability =2/6=1/3

Hence 1/3 is the probability  that the two numbers are multiples of 3 after replacing first

To learn more on probability click:

https://brainly.com/question/11234923

#SPJ2

Greatest common factor of 15,75

Answers

15........hope it helps

The greatest common factor is fifteen

Which of the following choices is NOT one of the six tenses of verbs?

past participle
future perfect
future
present perfect

Answers

Answer:

past participle

Step-by-step explanation:

all of the other ones are correct

29
A person invests $5000 in a bank account paying 4.5% interest compounded continously. To the nearest tenth
of a year, how long must the person leave the money in the bank until it reaches $10,200?

6.9 years
10.2 years
20.1 years
15.8 years

Answers

Answer

15.8

Step-by-step explanation:

When multiplying fractions we don’t have to worry about finding (blank) why?
SOMEONE HELP PLEASEEEEEEEE

Answers

Answer:

a common denominator

Step-by-step explanation:

I can confirm that answer

Enter the slope-intercept equation of the line shown below. ??!!!!!

Answers

Answer:

y=2x+4

Step-by-step explanation:

2x is the gradient and the y intercept is 4 so we just put them into the equation y=mx+c

is 3 bigger than 3.3

Answers

Answer:

No.

Step-by-step explanation:

3.3 is bigger than 3 by .3: )

Answer:

no.

3.3 > 3

Step-by-step explanation:

4x+2=-13 solve for x

Answers

Answer:

Solution given

4x+2=-13

subtract each term by 2

4x+2-2=-13-2

divide both side by 4

4x/4=-15/4

we get

x=-15/4

is a required answer.

Let's solve:

[tex]4x+2=−13[/tex]

Step 1: Subtract 2 from both sides.

[tex]4x+2−2=−13−2 \\ 4x = - 15[/tex]

Step 2: Divide both sides by 4.

[tex] \frac{4x}{4} = \frac{ - 15}{4} [/tex]

Answer:

[tex] \frac{ - 15}{4} [/tex]

I keep getting the wrong answers someone help please.

Answers

Answer:

1. 8.9

2. 14.5

3. 10.3

4. 18.8

5. 8.0

6. 15.0

(All to the nearest tenth)

The code is the sum of all missing sides

So adding all

=75.5

If each square on the grid represents 400 miles how many miles would Jacob's family travel in total

Answers

Answer:

80miles

Step-by-step explanation:

400=L

L[tex]\sqrt{400[/tex]

=20

to find p

4L

4(20=80

Answer this for me real quick

Answers

Answer:

[tex] \frac{x}{ {a}^{2} } [/tex]

Step-by-step explanation:

Matthhh

Answer:

x/a^2

Step-by-step explanation: Please tell me if this is right or wrong

Explain how
you know you would use sine, cosine or tangent to
solve this. Explain thorougly
C
X
10
B В

Answers

Answer:

To solve for x,  I would use Cosine.

This is because cosine holds the ratio of adjacent/hypotenuse. Based on the diagram, we can see that HYPOTENUSE = x, so we are solving for x. We know the angle, is 17 degrees. Lastly, we know the triangle leg ADJACENT to the angle is 10 units long. So we would use cosine, implementing the ratio adjacent/hypotenuse. Solving this, we would use cos(17)=10/x. Then our goal is to isolate x, so cos(17)=10/x becomes cos(17)*x=10, we are still trying to isolate x, so, x=10/cos(17). Therefore, our answer  x = 10.457 units. cosine would be the best way to go.

Step-by-step explanation:

Priyah’s weekly earnings were proportional to the number of hours she worked. The table shows the number of hours Priyah worked and the amount she earned. How much money did Priyah earn per hour?

Answers

Answer:

$17.50 is how much Priyah makes per hour

Plz help me anyone it’s being timed

Answers

Answer:

consistent.

Step-by-step explanation:

if lines cross they're consistent. If they dont they're inconsistent and if they overlap completely they're equivalent

Please help with this

Answers

Answer:

A

Step-by-step explanation:

The best way to prove the answer is to equate the two equation and solve for the x-coordinate..however in these equation the x value is zero so the y value will alternatively be zero hence there lines consist of no points of intersection

im giving points and brainliest​

Answers

Answer:

cool

Step-by-step explanation:

ok

Please help me ASAP And show work please

Answers

Answer:

X = 11

Step-by-step explanation:

3^(x-7) = 81

Find what exponent makes three into 81

The answer: x = 11

Answer:

x = 11

Step-by-step explanation:

Given

[tex]3^{x-7}[/tex] + 4 = 85 ( subtract 4 from both sides

[tex]3^{x-7}[/tex] = 81

[tex]3^{x-7}[/tex] = [tex]3^{4}[/tex]

Since the bases on both sides are equal, both 3 then equate the exponents

x - 7 = 4 ( add 7 to both sides )

x = 11

PLEASE I NEED HELP I DONT UNDERSTAND HOW TO DO ILL GIVW MORE IF RIGHT

Answers

Answer: Choice D

[tex]\frac{9\sqrt{2}}{2}[/tex]

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

Explanation:

We have a 45-45-90 triangle. If x is the leg length, then y = x*sqrt(2) is the hypotenuse.

Solving for y gets us [tex]x= \frac{y}{\sqrt{2}} = \frac{y\sqrt{2}}{2}[/tex]

In this case, y = 9 is the hypotenuse which then leads to choice D.

------------

Another way to find the answer is to use the pythagorean theorem

a = x and b = x are the two congruent legs

c = 9 is the hypotenuse

Solving a^2+b^2 = c^2, aka x^2+x^2 = 9^2, will lead to [tex]x = \frac{9\sqrt{2}}{2}[/tex]

How much would you pay for a shirt that is marked at $85, but is on sale for 30% off? (no Tax)​

Answers

Answer:

59.50

Step-by-step explanation:

Can someone explain this to me I already know the answer is 50 but how is it 50?

Answers

Angle 10 is 140 degrees

Angle 2 = Angle 10 = 140 degrees (Vertically Opposite Angles)

Angle 5 + Angle 4 = Angle 2 (Corresponding Angles)
Angle 5 + Angle 4 = 140
90 + Angle 4 = 140 (Angle 5 is 90 degrees because c is perpendicular to d)
Angle 4 = 50

Please help me its 2:24am and im really tired but im trynna get this done so please someone help

Answers

THE CORRECT ANSWER IS 57 CM³!

The weight of oranges growing in an orchard is normally distributed with a mean weight of 5 oz. and a standard deviation of 0.5 oz. From a batch of 1500 oranges, how many would be expected to weight less than 5 oz., to the nearest whole number?

Answers

Answer:

The interval that would represent weights of the middle 95% of all oranges from this orchard is from 5 oz to 7 oz.

Step-by-step explanation:

The Empirical Rule states that, for a normally distributed random variable:

68% of the measures are within 1 standard deviation of the mean.

95% of the measures are within 2 standard deviation of the mean.

99.7% of the measures are within 3 standard deviations of the mean.

In this problem, we have that:

Mean = 6

Standard deviation = 0.5

Middle 95% of weights:

By the Empirical Rule, within 2 standard deviations of the mean.

6 - 2*0.5 = 5

6 + 2*0.5 = 7

The interval that would represent weights of the middle 95% of all oranges from this orchard is from 5 oz to 7 oz.

how to write a relative frequency

Answers

Answer:

To find a relative frequency you need to divide the total number of x in the frequency to the total number. This can be represented as a fraction, decimal,  or percent.

Step-by-step explanation:

For example,

The ball landed 3 times out of 40.

3/40 = 7.5%

Step-by-step explanation:

To find the relative frequencies, divide each frequency by the total number of students in the sample–in this case, 20. Relative frequencies can be written as fractions, percents, or decimals. Cumulative relative frequency is the accumulation of the previous relative frequencies.

Example: Your team has won 9 games from a total of 12 games played: the Frequency of winning is 9. the Relative Frequency of winning is 9/12 = 75%

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