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3 years ago

What is -0.8+1.4n=2+0.7n

Mathematics

1 answer:

Sergio [31]3 years ago

6 0

Answer:

n=4

Step-by-step explanation:

To solve combine your like terms.

You can start by adding 0.8 to both sides and subtracting 0.7n from both sides.

$-0.8+1.4n=2+0.7n\\1.4n=2.8+0.7n\\0.7n=2.8$

Next, divide both sides by 0.7 to isolate for n.

$0.7n=2.8\\n=4$

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4+3(2r+2s)+3r Simplify this expression

Ipatiy [6.2K]

Hello!

First you can distribute the 3

4 + 6r + 6s + 3r

Then you combine like terms

4 + 9r + 6s

The answer is 9r + 6s + 4

Hope this helps!

3 0

3 years ago

Tom has 2 more than 5 times the number of CD’s that Jane has. Jane has 5 CD’s. Write an

Soloha48 [4]

Step-by-step explanation:

t=2+5×j

j=5

t=2+5×5

t=27

3 0

3 years ago

Read 2 more answers

Suppose the waiting times in an emergency room are normally distributed with a mean (mean) of 40 and a standard deviation (sigma

kipiarov [429]

Answer:

0.68269

Step-by-step explanation:

When we are to find the z score for population where a random sample is picked, the z.score formula we use is

z = (x-μ)/Standard error, where

x is the raw score,

μ is the population mean

Standard error = σ/√n

σ is the population standard deviation

n = random number of samples

For : x = 38 minutes, μ = 40, σ = 10, n = 5

z = 38 - 40/10 /√25

= -2/10/5

= -2/2

= -1

Determining the probability value using z table

P(x = 38) = P(z = -1)

= 0.15866

For : x = 42 minutes, μ = 40, σ = 10, n = 25

z = 42 - 40/10 /√25

= 2/10/5

= 2/2

= 1

Determining the probability value using z table

P(x = 42) = P(z = 1)

= 0.84134

The probability that their average waiting time will be between 38 and 42 minutes is calculated as

P(-Z<x<Z)

= P(-1 < x < 1)

= P(z = 1) - P(z = -1)

= 0.84134 - 0.15866

= 0.68269

Therefore, the probability that their average waiting time will be between 38 and 42 minutes is 0.68269

3 0

3 years ago

1/8 - 1/7 please :DDDDDDDDD

ira [324]

Answer:

-1/56

Step-by-step explanation:

6 0

3 years ago

Read 2 more answers

Professor Doom has applied to the town planning board to build a Villain's Lair in a suburban neighborhood. The local residents

tester [92]

Answer:

Check explanation below.

Step-by-step explanation:

Hello!

The objective of this experiment is to test if doctor Doom is controlling the neighbors' minds from his new Lair. To test this a random sample of 11 neighbors was taken and a "free will" test was administrated before the Villain's Lair was constructed and again after it was finished.

This experiment type where you have a single sample and the variable is measured "before" and "after" applying a treatment (in this case, that doctor Doom has moved into town) is a classic example of a paired sample test. You have two dependent variables, X₁: "Results of the free will test before Dr. Doom Lair is constructed" and X₂: "Results of the free will test after Dr. Doom Lair is constructed", with these variables you can establish a new variable, Xd, that I'll define as " X₁- X₂", and the objective of my hypothesis test will be to know if there is any change after the Lair is done, if there is, in fact, a change then the population mean of the difference will be nonzero, symbolically: μd ≠ 0

Using the data I've calculated the summary measures for Xd:

sample mean: Xd[bar]= 3.18

sample standard deviation: Sd= 5.44

The statistic hypothesis is:

H₀: μd = 0

H₁: μd ≠ 0

α: 0.05

(There is no signification level specified, so I've chosen the most common one)

Assuming that the variable difference, Xd, has a normal distribution, and with unknown population variance, the best statistic to use is the Students-t for paired samples:

t= Xd[bar] - μd ~t $_{n-1}$

Sd/√n

This test is two-tailed, so you will reject at low values of the statistic or at high values of it.

$t_{n-1;\alpha/2 } = t_{10; 0.025} = -2.228$

$t_{n-1; 1-\alpha /2} = t_{10; 0.975} = 2.228$

If t ≤ -2.228 or t ≥ 2.228 then you reject the null hypothesis.

If -2.228 < t < 2.228 then you don't reject the null hypothesis.

t= Xd[bar] - μd = 3.18 - 0 = 1.94

Sd/√n 5.44/√11

Since the statistic value t= 1.94 then the decision is to not reject the null hypothesis.

So, with a significance level of 5% there is not enough evidence to reject the null hypothesis, this means that the population mean of the difference on the free will test results of the neighbors before and after the Villain's Lair was constructed is equal to cero. In other words, there is not enough evidence to conclude that Dr. Doom is controlling the neighbor's minds.

I hope it helps!

3 0

3 years ago