place parentheses in the equation below so that you solve by finding the difference between 28 and 3 Write the answer 4×7-3=

I need help with this I am giving 60 points

inna [77]

Answer:

<2 ≅<4 with reason of vertical angle theorem.

Step-by-step explanation:

The vertical angle theorem states that two opposite (non-adjacent) angles formed by 2 intersecting lines have equal measure. In this problem, we are given that the angles are vertical angles. So the statement is that <2 ≅<4 with reason of vertical angle theorem.

3 0

2 years ago

A distribution of values is normal with a mean of 220 and a standard deviation of 13. From this distribution, you are drawing sa

Paraphin [41]

Answer:

The interval containing the middle-most 48% of sample means is between 218.59 to 221.41.

Step-by-step explanation:

To solve this question, we need to understand the normal probability distribution and the central limit theorem.

Normal probability distribution

Problems of normally distributed samples are solved using the z-score formula.

In a set with mean $\mu$ and standard deviation $\sigma$ , the zscore of a measure X is given by:

$Z = \frac{X - \mu}{\sigma}$

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.

Central Limit Theorem

The Central Limit Theorem estabilishes that, for a normally distributied random variable X, with mean $\mu$ and standard deviation $\sigma$ , the sample means with size n can be approximated to a normal distribution with mean $\mu$ and standard deviation $s = \frac{\sigma}{\sqrt{n}}$

In this problem, we have that:

$\mu = 220, \sigma = 13, n = 35, s = \frac{13}{\sqrt{35}} = 2.1974$

Find the interval containing the middle-most 48% of sample means:

50 - 48/2 = 26th percentile to 50 + 48/2 = 74th percentile. So

74th percentile

value of X when Z has a pvalue of 0.74. So X when Z = 0.643.

$Z = \frac{X - \mu}{\sigma}$

By the Central Limit Theorem

$Z = \frac{X - \mu}{s}$

$0.643 = \frac{X - 220}{2.1974}$

$X - 220 = 0.643*2.1974$

$X = 221.41$

26th percentile

Value of X when Z has a pvalue of 0.26. So X when Z = -0.643

$Z = \frac{X - \mu}{s}$

$-0.643 = \frac{X - 220}{2.1974}$

$X - 220 = -0.643*2.1974$

$X = 218.59$

The interval containing the middle-most 48% of sample means is between 218.59 to 221.41.

5 0

3 years ago

The sum of the digits of a 2-digit number is 10. If 18 is added to the number, the digits of the new number are those of the ori

Aliun [14]

Answer:

46

Step-by-step explanation:

Let $(ab)$ represent a number with $a$ in the ten's position and $b$ is the one's position.

This means $(ab)$ actually has value of $10a+b$ .

We are given the sum of those digits of $(ab)$ is 10; this means $a+b=10$ .

It says if 18 is added to the number $(ab)$ , then the result is $(ba)$ .

So $(ab)$ has value $10a+b$ and

$(ba)$ has value $10b+a$ .

We are given then:

$(ab)+18=(ba)$

$10a+b+18=10b+a$

Subtract $10a$ on both sides:

$b+18=10b+a-10a$

Simplify:

$b+18=10b-9a$

Subtract $b$ on both sides:

$18=10b-b-9a$

$18=9b-9a$

Divide both sides by 9:

$2=b-a$

Rearrange by commutative property:

$2=-a+b$

So the system of equations we want to solve is:

$a+b=10$

$-a+b=2$

-------------------------Add equations together (this will eliminate the variable $a$ and allow you to go ahead and solve for $b$ :

$0+2b=12$

$2b=12$

Divide both sides by 2:

$b=\frac{12}{2}$

Simplify:

$b=6$

If $b=6$ and $a+b=10$ , then $a=4$ . $a=4$ since 4+6=10.

So the original number is (46).

18 more than 46 is 18+46=(64) which is what we wanted.

We also have the sum of 4 and 6 is 10 as well.

7 0

3 years ago

20. The total mass of three boxes, A, B, and C, is 1.95 kg. The mass of Box A is 700 g. The mass of Box B is 4 times the mass of

Ksju [112]

Answer:

Step-by-step explanation:

LET'S DO THIS!

Total mass of A, B and C = 1.95kg

Mass of A = 700 kg

Mass of B = 4x the mass of c (4 x C) which is 4c

Mass of C = ? ( let's call it C )

<h3>Adding all together </h3>

700 + 4c + C = 1.95

<h3>Add like terms</h3>

700 + 5C = 1.95

5C = 1.95 - 700

5C = -698.05

C = -698.05 ÷ 5

<h3>To find B now </h3><h3>Remember they said B is 4 times the mass of C and C = -139.61</h3>

therefore B = 4 × -139.61

<h3>To check if we are correct, we add the masses of A, B and C to see if it equals their total mass which is 1.95kg</h3>

<h3>Using your calculator: </h3>

= 700 + ( -558.44 ) + ( -139.61 )

= 700 - 558.44 -139.61

= 1.95 kg

Which makes us CORRECT ✅.

<h3>Hope this helps.</h3><h3>Good luck ✅.</h3>

5 0

1 year ago

Read 2 more answers

Please evaluate this

siniylev [52]

Answer:

$y = 2 \: and \: x = 2.5$

y=2x-3

2=2

$y = 2x - 3 \\ y = |2 \times 2.5| - 3 \\ y = 5 - 3 \\ y = 2 \\$

And

8 0

3 years ago