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3 years ago

What is the answer to this problem? 0.35 + 0.27 = ?

Mathematics

2 answers:

charle [14.2K]3 years ago

6 0

Hey there!

First off, you can add 35 and 27 . . .

35 + 27 = 62

Then add the zero and decimal point . . .

= 0.62

0.35 + 0.27 = 0.62 <-------

Your answer is option B.

Hope this helps you.
Have a great day!

gavmur [86]3 years ago

3 0

Have you never added 2-digit numbers?
35 +27 = (30 +20) +(5 +7) = 50 +12 = 62

35/100 +27/100 = (35 +27)/100 = 62/100
0.35 +0.27 = 0.62

The basic idea, taught in 3rd grade, is to line up the decimal points of the numbers, add enough zeros on the right to make the numbers all have the same number of digits to the right of the decimal point, then add in the usual way. The sum has the decimal point aligned with the rest of the numbers.

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A is correct because 445.50 Divided By 150 is Equal to $2.97.

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2 years ago

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Every dimension of a triangular pyramid is multiplied by 10 to produce a new figure that is geometrically similar. What effect d

Lesechka [4]

<h3>Answer: Choice C</h3>

The surface area of the pyramid is multiplied by 100.

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

Explanation:

Consider a square that is 3 by 3. Its area is 3*3 = 9.

Then we'll multiply each dimension by 10 to get a 30 by 30 square. The new larger area is 30*30 = 900. The jump from the old area (9) to the new area (900) is "times 100". We can write 100 as 10^2, where the base of that exponential is the scale factor 10.

This idea can apply to any surface area and not just squares. This is why the surface area of the enlarged pyramid is 100 times that of the original pyramid.

new surface area = 100*(old surface area)

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2 years ago

The head librarian at the Library of Congress has asked her assistant for an interval estimate of the mean number of books check

Verdich [7]

Answer:

$n=(\frac{1.960(150)}{90})^2 =10.67 \approx 11$

So the answer for this case would be n=11 rounded up to the nearest integer

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".

$\bar X$ represent the sample mean for the sample

$\mu$ population mean (variable of interest)

$\sigma =150$ represent the population standard deviation

n represent the sample size

Solution to the problem

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

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

The confidence interval for this case is given by: (740, 920)

We can find the estimate for the mean and we got:

$\bar X = \frac{740+920}{2} = 830$

and the margin of error is given by :

$ME = \frac{920-740}{2}= 90$

The margin of error is given by this formula:

$ME=z_{\alpha/2}\frac{s}{\sqrt{n}}$ (a)

And on this case we have that ME =90 and we are interested in order to find the value of n, if we solve n from equation (a) we got:

$n=(\frac{z_{\alpha/2} s}{ME})^2$ (b)

The critical value for 95% of confidence interval now can be founded using the normal distribution. And in excel we can use this formla to find it:"=-NORM.INV(0.025;0;1)", and we got $z_{\alpha/2}=1.960$ , replacing into formula (b) we got: