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2 years ago

In 2013, the population of China was estimated to be 1,360,760,100. Round off the number of people

Mathematics

2 answers:

Aleksandr [31]2 years ago

7 0

Answer:

a) 1,360,760,000

b) 1,361,000,000

c) 1,400,000,000

d) 1,360,800,000

Step-by-step explanation:

We have to round off the given population number to certain digits.

The following are the rules to round of a number:

First identify the digit to be rounded.
If this digit is followed by 5,6,7,8,9 then we round up the number that is increase the digit by 1 and all the numbers to right becomes zero.
If this digit is followed by 0,1,2,3,4 then we round down the number that is decrease the digit by 1 and all the numbers to right becomes zero.

a) to the nearest thousand.

Thousands place: 0

Right Digit: 1

We round down the number

Rounded to the nearest 1,000 or t he thousands Place = 1,360,760,000

b) to the nearest million

Millions place: 0

Right Digit: 7

We round up the number

Rounded to the nearest million places = 1,361,000,000

c) to nearest hundred million

Hundred million place: 3

Right Digit: 6

We round up the number

Rounded to the nearest million places = 1,400,000,000

d) to the nearest hundred thousand.

hundred thousand place: 7

Right Digit: 6

We round up the number

Rounded to the nearest million places = 1,360,800,000

yarga [219]2 years ago

6 0

Answer:

Step-by-step explanation:

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Answer:

Option A

Step-by-step explanation:

A type I error is committed when a researcher rejects the null hypothesis when it is actually true.

The null hypothesis is: U <= 50%

The alternative is: U > 50%

Thus, the principal could have committed an error by rejecting null hypothesis and concluding that more than 50% of students want earlier lunch, when in actuality 50% or less want earlier lunch.

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2 years ago

A bicycle tire has a radius of 5 inches. To the nearest inch, how far does the tire travel when it makes 8 revolutions?

Pani-rosa [81]

Answer:

251 inches

Step-by-step explanation:

c = 2πr

c = 2(3.14)(5) = 31.4

31.4 x 8 rev. = 251 inches

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2 years ago

Anthony, Brian and Chris are hired for a job. If Anthony and Brian are working together they will finish the job in minutes. If

Tcecarenko [31]

Answer:

12.5

Step-by-step explanation:

Let individual time taken by Anthony, Brian and Chris = t1 , t2 , t3 respectively

So, total time taken by A & B = 1 / t1 + 1 / t2 , lets suppose = 10 {i}

Total time taken by A & C = 1 / t1 + 1 / t3 , lets suppose = 15 {ii}

Total time taken by B & C = 1 / t2 + 1 / t3 , lets suppose = 20 {iii}

From {i} , 1 / t2 = 10 - 1 / t1

From {ii} 1 / t1 = 15 - 1 / t3

By above two eqtns , 1 / t2 = 10 - (15 - 1 / t3)

1 / t2 = 1 / t3 - 5

Putting in {iii} , 1 / t3 - 5 + 1 / t3 = 20

2 / t3 = 25

t3 = 12.5

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2 years ago

The spinner shown has eight equal-sized sections. The pointer lands on an even number 135 times out of 250 spins. Which of the f

forsale [732]

Answer:

A and D

Step-by-step explanation:

Here, we shall be evaluating the validity of the statements;

A. Yes, A is true

There are four even numbers 2,4,6 and 8 and 4 odd number 1,3,5,7; The landing should be equal at 125 each

B. This is wrong

It is supposed to land half of the number of time s which is half of 250 and that is 125

C.This is wrong

The numbers greater than 4 are 5,6,7,8

Now, the probability should be 4/8 = 1/2 and that is 50%

D. This is correct

Number of times we have a landing on odd numbers is 250-135 = 115

The experimental probability of landing on an odd number is thus 115/250 = 0.46 which is 46%

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2 years ago

Ice cream usually comes in 1.5-quart boxes (48 fluid ounces), and ice cream scoops hold about 2 ounces. However, there is some v

Troyanec [42]

Answer:

(a) The expected value and standard deviation of the amount of ice cream served at the party are 54 ounces and 1.25 ounces respectively.

(b) The expected value and standard deviation of the amount of ice cream left in the box after scooping out one scoop are 46 ounces and 1.031 ounces respectively.

Step-by-step explanation:

The random variable X and Y are defined as follows:

X = amount of ice cream in the box

Y = amount of ice cream scooped out

The information provided is:

E (X) = 48

SD (X) = 1

V (X) = 1

E (Y) = 2

SD (Y) = 0.25

V (Y) = 0.0625

(a)

The total amount of ice-cream served at the party can be expressed as:

X + 3Y.

Compute the expected value of (X + 3Y) as follows:

$E(X+3Y)=E(X)+3E(Y)\\= 48+(3\times2)\\=48+6\\=54$

Compute the variance of (X + 3Y) as follows:

$V(X+3Y) = V (X)+3^{2}V(Y)+2\times 3Cov (X,Y)\\=1+(9\times0.0625)+0\\=1.5625$

Then the standard deviation of (X + 3Y) is:

$SD(X + 3Y) =\sqrt{V(X + 3Y)}\\\sqrt{1.5625}\\=1.25$

Thus, the expected value and standard deviation of the amount of ice cream served at the party are 54 ounces and 1.25 ounces respectively.

(b)

The amount of ice-cream left in the box after scooping out one scoop is represented as follows:

X - Y.

Compute the expected value of (X - Y) as follows:

$E(X-Y)=E(X)-E(Y)\\=48-2\\=46$

Compute the variance of (X - Y) as follows:

$V(X - Y) =V(X)+V(Y)-2Cov(X,Y)\\=1+0.0625-0\\=1.0625$

Then the standard deviation of (X - Y) is:

$SD(X-Y) =\sqrt{V(X -Y)}\\\sqrt{1.0625}\\=1.031$

Thus, the expected value and standard deviation of the amount of ice cream left in the box after scooping out one scoop are 46 ounces and 1.031 ounces respectively.

(c)

The variance of the sum or difference of two variables is computed by adding the individual variances. This is because the variance of each variable is dependent on the others.

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2 years ago