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2 years ago

Please Help!!! . . . . .

Mathematics

1 answer:

Ede4ka [16]2 years ago

8 0

PEMDAS. parenthesis, exponents, multiple or divide (whichever come first from left to right), add or subtract (whichever comes first from left to right)

So first do stuff in parenthesis.
Then do divide because thats next on the list and it happens earlier than the multiply one.

So, A

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If the price of a purse increased from $45 to $54, what was the percent of increase

Marrrta [24]

If you set it up in cross multiplication then you would have (x/100 = 45/54) then cross multiply so then i would look like this (54x/4,500) so from there you would divide 54 from 4,500 i hope this helps in any way oh and it should come up to be 83.3333333 which would be 83% lol

5 0

4 years ago

Read 2 more answers

Multiply and simplify the following expression -4√15 x(-√3)

larisa [96]

Answer:

$\large\boxed{12\sqrt5}$

Step-by-step explanation:

$\text{Use}\ \sqrt{ab}=\sqrt{a}\cdot\sqrt{b}\\-----------------\\\\-4\sqrt{15}\cdot\left(-\sqrt3\right)=4\sqrt{(15)(3)}=4\sqrt{5\cdot3\cdot3}=4\sqrt5\cdot\sqrt9\\\\=4\sqrt5\cdot3=12\sqrt5$

6 0

3 years ago

Solve the following system of equations by linear combination: 3d – e = 7 d + e = 5

SashulF [63]

3d - e = 7d + e = 5 ⇒ 3d - e = 5
7d + e = 5

3d - e = 5
7d + e = 5 +
-----------------------
10d / = 10
10d = 10
d = 10/10
d = 1

7d + e = 5
7×1 + e = 5
7 + e = 5
e = 5 - 7
e = -2

8 0

3 years ago

Diana ,and Jennifer and Christina are making class for the craft fair Diana has made three tenths of her Jennifer has made Two f

Sladkaya [172]

A- Christina
B-Diana

4 0

3 years ago

An educational psychologist wishes to know the mean number of words a third grader can read per minute. She wants to make an est

nirvana33 [79]

Answer:

The 80% confidence interval for the mean number of words a third grader can read per minute is between 40.4 wpm and 40.8 wpm.

Step-by-step explanation:

We have that to find our $\alpha$ level, that is the subtraction of 1 by the confidence interval divided by 2. So:

$\alpha = \frac{1-0.8}{2} = 0.1$

Now, we have to find z in the Ztable as such z has a pvalue of $1-\alpha$ .

So it is z with a pvalue of $1-0.1 = 0.99$ , so $z = 1.28$

Now, find M as such

$M = z*\frac{\sigma}{\sqrt{n}}$

In which $\sigma$ is the standard deviation of the population and n is the size of the sample.

$M = 1.28*\frac{4.1}{\sqrt{840}} = 0.2$

The lower end of the interval is the sample mean subtracted by M. So it is 40.6 - 0.2 = 40.4 words per minute.

The upper end of the interval is the sample mean added to M. So it is 40.6 + 0.2 = 40.8 words per minute.

The 80% confidence interval for the mean number of words a third grader can read per minute is between 40.4 wpm and 40.8 wpm.

3 0

4 years ago