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2 years ago

How do I solve this??

Mathematics

1 answer:

olga_2 [115]2 years ago

5 0

Answer:

Step-by-step explanation:

x + 29 + 12 = 89

x + 41 = 89

x = 48 for <CED

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To receive a grade of A on an 80-question test, 90% of the questions must be answered correctly. What is the maximum number of q

marta [7]

Answer:

The answer would be 8.

Step-by-step explanation:

This is a percentage question, and I have struggled with these before but this is the easiest way to solve it given these certain criteria.

Alright, so it's given that:

A) 90%= an A grade

and

B) This is an 80-question test.

Given these, we can do the following:

90% times 80, which equals 72.

Just to check, we know that to convert percentages to fractions, we move the decimal two spots to the left, therefore 90%= 0.90, or 0.9. We take 72 and divide it by 80, and we get 0.9, thus showing that it is correct.

Then, we do 80-72 and using simple math we get 8.

8 0

3 years ago

Simplify the following expressions in indices (2 x 103 x 3 x 105)/2 x 10-2

Maurinko [17]

(2 x 103 x 3 x 105) = 64890

2 x 10 -2 = 20 - 2 = 18

64890 / 18

3605

Or (206 x 315) / 20 - 2

3 0

3 years ago

Evaluate the following

Lana71 [14]

Answer:

314

Step-by-step explanation:

c = 100(3.14)

c = 314

3 0

3 years ago

Read 2 more answers

The graph of the function y = x² - x - 2 is shown below.

velikii [3]

Y=(x+1)(x-1) this is factored out

5 0

3 years ago

The desired percentage of SiO2 in a certain type of aluminous cement is 5.5. To test whether the true average percentage is 5.5

miskamm [114]

Answer:

z=-3.25

$p_v =2*P(z$

Step-by-step explanation:

1) Data given and notation

$\bar X=5.24$ represent the mean production for the sample

$\sigma=0.32$ represent the sample standard deviation for the sample

$n=16$ sample size

$\mu_o =5.5$ represent the value that we want to test

$\alph=0.05a$ represent the significance level for the hypothesis test.

z would represent the statistic (variable of interest)

$p_v$ represent the p value for the test (variable of interest)

Part a: State the null and alternative hypotheses.

We need to conduct a hypothesis in order to check if the mean production is different from 5.5 tons, the system of hypothesis would be:

Null hypothesis: $\mu =5.5$

Alternative hypothesis: $\mu \neq 5.5$

If we analyze the info given we know the population deviation so is better apply a z test to compare the actual mean to the reference value, and the statistic is given by:

$z=\frac{\bar X-\mu_o}{\frac{s}{\sqrt{n}}}$ (1)

z-test: "Is used to compare group means. Is one of the most common tests and is used to determine if the mean is (higher, less or not equal) to an specified value".

Calculate the statistic

We can replace in formula (1) the info given like this:

$z=\frac{5.24-5.5}{\frac{0.32}{\sqrt{16}}}=-3.25$

P-value

Since this is a two side test the p value would be:

$p_v =2*P(z$

Conclusion

If we compare the p value and the significance level given $\alpha=0.05$ we see that $p_v$ so we can conclude that we have enough evidence to reject the null hypothesis, so we can conclude that the production its significant different compared to the desired percentage of SiO2 of 5.5 at 5% of signficance.

7 0

3 years ago