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2 years ago

Is 51x51 is even or odd

Mathematics

2 answers:

Nutka1998 [239]2 years ago

8 0

51times51 is an odd number

AURORKA [14]2 years ago

3 0

You can predict that it's odd because the end of the 2 numbers is 1 and 1 x 1 is 1 and one is an odd number. (answer is odd)

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Mrs. Salas drives 115 miles per week to give 9 voice lessons. She deducts the cost of eight gallons of gasoline at $2 per gallon

ladessa [460]

the answer is $299. If you write an equation, it would be x=35(9)-16. $35 each for 9 lessons. And 2*8= 16.

x=35(9)-16

x=315-16

x=299

7 0

2 years ago

Find the area of the figure. If you need to use Pi in your computation, approximate its value as 3.14. Round to the nearest hund

arsen [322]

Answer:

area of figure= area of rectangle+area of semi-circle

area of rectangle= length ×width

5×4

= 20in²

area of semi circle= 1/2πr²

1/2×22/7×2×2

22×2

44

= 6.29in²

area of figure= 20+6.29

= 26.29in²

4 0

2 years ago

23. A certain type of gasoline is supposed to have a mean octane rating of at least 90. Suppose measurements are taken on of 5 r

Nostrana [21]

Answer:

a) $p_v =P(Z$

b) Since $p_v$ we can reject the null hypothesis at the significance level given. So based on this we can commit type of Error I.

Because Type I error " is the rejection of a true null hypothesis".

c) $P(\bar X >90)=1-P(Z$

$1-P(Z$

d) For this case we need a z score that accumulates 0.02 of the area on the right tail and 0.98 on the left tail and this value is z=2.054

And we can use this formula:

$2.054=\frac{90-89}{\frac{0.8}{\sqrt{n}}}$

And if we solve for n we got:

$n = (\frac{2.054 *0.8}{1})^2=2.7 \approx 3$

Step-by-step explanation:

Previous concepts and data given

The margin of error is the range of values below and above the sample statistic in a confidence interval.

Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".

We can calculate the sample mean and deviation with the following formulas:

$\bar X = \frac{\sum_{i=1}^n X_i}{n}$

$s=\sqrt{\sum_{i=1}^n (X_i -\bar X)^2}{n-1}$

$\bar X=88.96$ represent the sample mean

$s=1.011$ represent the sample standard deviation

n=5 represent the sample selected

$\alpha$ significance level

State the null and alternative hypotheses.

We need to conduct a hypothesis in order to check if the mean is less than 90, the system of hypothesis would be:

Null hypothesis: $\mu \geq 90$

Alternative hypothesis: $\mu < 90$

If we analyze the size for the sample is < 30 and we don't know the population deviation so is better apply a t test to compare the actual mean to the reference value, and the statistic is given by:

$z=\frac{\bar X-\mu_o}{\frac{\sigma}{\sqrt{n}}}$ (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:

$z=\frac{88.96-90}{\frac{0.8}{\sqrt{5}}}=-2.907$

Part a

P-value

First we need to calculate the degrees of freedom given by:

$df=n-1=5-1 = 4$

Then since is a left tailed test the p value would be:

$p_v =P(Z$

Part b

Since $p_v$ we can reject the null hypothesis at the significance level given. So based on this we can commit type of Error I.

Because Type I error " is the rejection of a true null hypothesis".

Part c

We want this probability:

$P(\bar X$

The best way to solve this problem is using the normal standard distribution and the z score given by:

$z=\frac{x-\mu}{\frac{\sigma}{\sqrt{n}}}$

If we apply this formula to our probability we got this:

$P(\bar X >90)=1-P(Z$

$1-P(Z$

Part d

For this case we need a z score that accumulates 0.02 of the area on the right tail and 0.98 on the left tail and this value is z=2.054

And we can use this formula:

$2.054=\frac{90-89}{\frac{0.8}{\sqrt{n}}}$

And if we solve for n we got:

$n = (\frac{2.054 *0.8}{1})^2=2.7 \approx 3$

7 0

3 years ago

Julie works Sunday, monday, and Wednesday 10 hrs. each day. on Tuesday andThursday and Friday are 7 hours each day. She's off on

Oliga [24]

(Sunday, Monday, Wednesday) 3X10=30 hours

(Tuesday, Thursday, Friday) 3X7= 21 hours

30 hours + 21 hours = 51 Hours.

She made $612.00 for 51 hours. $612.00 divided by 51= $12.00 per hour

8 0

3 years ago

Help please help please help please

marissa [1.9K]

Answer:

x=5

Step-by-step explanation:

I'm pretty sure it's x=5 because if you multiply that and the quadratic function it is -12 1/2 not 12 1/2 (hope this helps :)

8 0

3 years ago

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