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3 years ago

The ratio of boys to girls in a group is 7:2. If there are 60 more boys than girls, work out how many girls there are.

Mathematics

1 answer:

zimovet [89]3 years ago

7 0

Answer:

Step-by-step explanation:

So, kids are divided into 8 total parts.

7 - 1 = 6 more parts that are boys. The 48 extra boys are those 6 parts.

48/6 = 8 boys per part

All parts have the equal number of kids, so one part girls also has 8.

There are 8 girls (and 56 boys. 8:56 = 1:7).

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A submarine was situated 800 feet below sea level.

Ghella [55]

Answer:

New position = -525 ft or 525 ft below the sea level

Step-by-step explanation:

Lets h be the height of the sea.

Given:

A submarine was situated 800 feet below sea level.

It is ascends 275 feet.

We know that h = 0 on the surface of the sea.

When we go below the surface vertically inside the sea the height will become negative.

So the submarine was situated h = -800 feet below the sea level, and it is ascends 275 feet from -800 feet.

So the new height of the submarine is.

$h = -800 + 275$

$h = -525\ ft$

Therefore the new position of the submarine is 525 below the sea level.

8 0

3 years ago

An artist designed a metal structure in the shape of a pyramid with dimensions as shown. A pyramid has a square base with side l

bagirrra123 [75]

Answer:

Step-by-step explanation:

In order to determine the number of

tiles she will need to cover the pyramid, we would apply the formula for determining the total surface area of a pyramid. It is expressed as

Total surface area = 1/2 × p × l + base area

Where

p represents the perimeter of the base

l represents the slant height of the triangular face

Since the base is a square, the perimeter, p is

12 × 4 = 48 feet

l = 15 feet

Base area = 12² = 144 ft²

Total surface area = (1/2 × 48 × 15) + 144 = 504 ft²

Since the artist decides to cover the metal structure with 1-foot square glass tiles, the number of tiles needed is

504/1 = 504 tiles

6 0

3 years ago

(5x^2+38x+18) divided (x+7) what is the quotient and the remainder

xxTIMURxx [149]

The quotient is 5x^2 + 3x -3 and the remainder is -3.

5 0

3 years ago

Can someone help me with this? It’s unit rates with price. Question: 6 feet of ribbon for $19.20

lbvjy [14]

Answer:

OOPEEEEEEEEEEEEEEEE

Step-by-step explanation:

The answer is,

4.53

8 0

3 years ago

Read 2 more answers

In an examination of purchasing patterns of shoppers, a sample of 16 shoppers revealed that they spent, on average, $54 per hour

Lesechka [4]

Answer:

$54-1.64\frac{21}{\sqrt{16}}=45.39$

$54 +1.64\frac{21}{\sqrt{16}}=62.61$

So on this case the 90% confidence interval would be given by (45.39;62.61)

Step-by-step explanation:

Previous concepts

A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population means lies between an upper and lower interval".

The margin of error is the range of values below and above the sample statistic in a confidence interval.

Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".

$\bar X=54$ represent the sample mean

$\mu$ population mean (variable of interest)

$\sigma=21$ represent the sample standard deviation

n=16 represent the sample size

Solution to the problem

The confidence interval for the mean is given by the following formula:

$\bar X \pm z_{\alpha/2}\frac{\sigma}{\sqrt{n}}$ (1)

Since the Confidence is 0.90 or 90%, the value of $\alpha=1-0.9=0.1$ and $\alpha/2 =0.05$ , and we can use excel, a calculator or a table to find the critical value. The excel command would be: "=-NORM.INV(0.05,0,1)".And we see that $z_{\alpha/2}=1.64$

Now we have everything in order to replace into formula (1):

$54-1.64\frac{21}{\sqrt{16}}=45.39$

$54 +1.64\frac{21}{\sqrt{16}}=62.61$

So on this case the 90% confidence interval would be given by (45.39;62.61)

4 0

3 years ago