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KatRina [158]
3 years ago
7

PLEASE HELP

Mathematics
2 answers:
polet [3.4K]3 years ago
4 0

Answer:

A = 3E

A + E = 56

3E + E = 56

4E = 56

E = 14

Elga is 14 years old.

Step-by-step explanation:

Could you please mark me as the brainliest answer

Romashka-Z-Leto [24]3 years ago
3 0

Answer:

Step-by-step explanation:

17.33

You might be interested in
Plz helppp I don’t understand
Dmitrij [34]

Answer:

5+x=-4, =9

Step-by-step explanation:

5+x=-4 Write equation

-5    -5 Subtract 5 from both sides to isolate x

 +x=-9

4 0
3 years ago
At the movie theater the blaine family spent $22.00 for twoadult tickets and three child tickets. the hooper family spent $18.50
Anika [276]
2a+3c=22.00 ......equation 1
a+4c=18.50  =>2a+8c=37.00 .....equation 2
subtract equation one from equation two: 
5c=37-22=15
c=3
a+4*3=18.50 =>a=6.50

for the Hu family: 3*6.50+1*3.00=22.50 dollars
3 0
3 years ago
Alyssa worked 2 part-time jobs and earned $181.50 for working a total of 24 hours at both jobs. She is paid $6.00 per hour at jo
jeka57 [31]

Answer:

Alyssa work at job A 9\ hours

Step-by-step explanation:

Let

x------> the number  of hours at work A

y------> the number  of hours at work B

we know that

x+y=24

y=24-x -----> equation A

6x+8.5y=181.5 -----> equation B

substitute equation A in equation B

6x+8.5(24-x)=181.5

6x+204-8.5x=181.5

8.5x-6x=204-181.5

2.5x=22.5

x=22.5/2.5

x=9\ hours

5 0
3 years ago
4. Trace metals in drinking water affect the flavor, and unusually high concentrations can be haz-
tresset_1 [31]

Answer:

There isn't enough evidence to suggest that the true average concentration in the surface water is different than the concentration in the bottom water.

Step-by-step explanation:

We want to test if the true average concentration in the surface water is different than the concentration in the bottom water.

For this, we obtain a new distribution that is the difference between zinc concentration at the bottom and at the top for the 6 samples

A B C D E F

Zinc on surface

0.411 0.238 0.390 0.410 0.605 0.609

Zinc on bottom

0.430 0.266 0.369 0.531 0.627 0.716

Difference (zinc at bottom - zinc at surface)

0.019 0.028 -0.021 0.121 0.022 0.107

We can the find the mean of the differences and the standard deviation of the sample of differences

Mean = xbar = (Σx)/N = (0.276/6) = 0.046

Standard deviation = σ = √{[Σ(x - xbar)²]/(N-1)}

We use (N - 1) because this distribution is that of a sample.

x = each variable

xbar = mean = 0.046

N = number of variables = 6

σ = 0.055612948132607 = 0.055613

For hypothesis testing, the first thing to define is the null and alternative hypothesis.

The null hypothesis plays the devil's advocate and usually takes the form of the opposite of the theory to be tested. It usually contains the signs =, ≤ and ≥ depending on the directions of the test.

While, the alternative hypothesis usually confirms the the theory being tested by the experimental setup. It usually contains the signs ≠, < and > depending on the directions of the test.

For this question, we want to test if the true average concentration in the surface water is different than the concentration in the bottom water.

Hence, the null hypothesis is that there isn't significant evidence to suggest that the true average concentration in the surface water is different than the concentration in the bottom water.

The alternative hypothesis is that there is significant evidence to suggest that the true average concentration in the surface water is different than the concentration in the bottom water.

Mathematically, if the mean of zinc concentration at the surface and the bottom are μ₁ and μ₂ respectively and the mean difference is μ = μ₂ - μ₁

The null hypothesis is represented as

H₀: μ = 0 or μ₂ = μ₁

The alternative hypothesis is represented as

Hₐ: μ ≠ 0 or μ₂ ≠ μ₁

To do this test, we will use the t-distribution because no information on the population standard deviation is known

So, we compute the t-test statistic

t = (x - μ₀)/σₓ

x = mean difference = 0.046

μ₀ = 0

σₓ = standard error = (σ/√n)

σ = 0.055613

n = Sample size = 6

σₓ = (0.055613/√6) = 0.0227

t = (0.046 - 0) ÷ 0.0227

t = 2.026 = 2.03

checking the tables for the p-value of this t-statistic

Degree of freedom = df = n - 1 = 6 - 1 = 5

Significance level = 0.05

The hypothesis test uses a two-tailed condition because we're testing in both directions.

p-value (for t = 2.03, at 0.05 significance level, df = 5, with a two tailed condition) = 0.098613

The interpretation of p-values is that

When the (p-value > significance level), we fail to reject the null hypothesis and when the (p-value < significance level), we reject the null hypothesis and accept the alternative hypothesis.

So, for this question, significance level = 0.05

p-value = 0.098613

0.098613 > 0.05

Hence,

p-value > significance level

This means that we fail to reject the null hypothesis & say that there isn't enough evidence to suggest that the true average concentration in the surface water is different than the concentration in the bottom water.

Hope this Helps!!!

5 0
3 years ago
Defenition of exponent
aivan3 [116]

An exponent is a quantity representing the power to which a given number or expression is to be raised, usually expressed as a raised symbol beside the number or expression (e.g. 3 in 23 = 2 × 2 × 2).

In other words, an exponent represents how many times you multiply (or divide) a value by itself.

5 0
3 years ago
Read 2 more answers
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