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3 years ago

How many numbers are prime between 40 and 50?

Mathematics

2 answers:

natali 33 [55]3 years ago

6 0

Step-by-step explanation:

Correct answer:

(The primes between 40 and 50 are 41, 43, and 47 - three.

lions [1.4K]3 years ago

5 0

Answer: The primes between 40 and 50 are 41, 43, and 47 - three.

Step-by-step explanation:

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For a science project, James needs to fill a tennis ball with sand but he doesn't know how much he will need. He measured the di

klio [65]

Do not go to that link it is a virus and if you go to “goggle” and press the camera icon on the top right and take a picture of the question you should get the answer there

8 0

3 years ago

Please help ASAP!

g100num [7]

So all you have to do to solve these problems is substitute the y coordinate and the x coordinate into the equation.

So question 1 would be true because when you substitute the numbers in it equals the y value.

Question 2 is (4, -7)

Question 3 is False

Question 4 is true

Question 5 is true

See if you can do the rest!

8 0

4 years ago

3.1 times 10 ^3 in ordinary form

Shkiper50 [21]

=3.1*10^3
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7 0

3 years ago

The price of lettuce was $1.25 one week and $1.50 the next week. Find the percent of increase.

melomori [17]

So the lettuce went up by 0.25 or 25c, now, if we take 1.25 to be the 100%, how much is 0.25 in percentage off of it?

$\bf \begin{array}{ccllll}
amount&\%\\
\text{\textemdash\textemdash\textemdash}&\text{\textemdash\textemdash\textemdash}\\
1.25&100\\
0.25&x
\end{array}\implies \cfrac{1.25}{0.25}=\cfrac{100}{x}\implies x=\cfrac{0.25\cdot 100}{1.25}$

8 0

3 years ago

SAT scores are normed so that, in any year, the mean of the verbal or math test should be 500 and the standard deviation 100. as

vovangra [49]

Answer:

a) $P(X>625)=P(\frac{X-\mu}{\sigma}>\frac{625-\mu}{\sigma})=P(Z>\frac{625-500}{100})=P(Z>1.25)$

$P(Z>1.25)=1-P(Z$

b) $P(400$

$P(-1$

c) $z=-0.842$

And if we solve for a we got

$a=500 -0.842*100=415.8$

So the value of height that separates the bottom 20% of data from the top 80% is 415.8.

Step-by-step explanation:

Previous concepts

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".

The Z-score is "a numerical measurement used in statistics of a value's relationship to the mean (average) of a group of values, measured in terms of standard deviations from the mean".

Part a

Let X the random variable that represent the SAT scores of a population, and for this case we know the distribution for X is given by:

$X \sim N(500,100)$

Where $\mu=500$ and $\sigma=100$

We are interested on this probability

$P(X>625)$

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

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

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

$P(X>625)=P(\frac{X-\mu}{\sigma}>\frac{625-\mu}{\sigma})=P(Z>\frac{625-500}{100})=P(Z>1.25)$

And we can find this probability using the complement rule and with the normal standard table or excel:

$P(Z>1.25)=1-P(Z$

Part b

We are interested on this probability

$P(400$

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

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

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

$P(400$

And we can find this probability with this difference:

$P(-1$

And in order to find these probabilities we can find tables for the normal standard distribution, excel or a calculator.

$P(-1$

Part c

For this part we want to find a value a, such that we satisfy this condition:

$P(X>a)=0.8$ (a)

$P(X$ (b)

Both conditions are equivalent on this case. We can use the z score again in order to find the value a.

As we can see on the figure attached the z value that satisfy the condition with 0.2 of the area on the left and 0.8 of the area on the right it's z=-0.842. On this case P(Z<-0.842)=0.2 and P(Z>-0.842)=0.8

If we use condition (b) from previous we have this:

$P(X$

$P(z$

But we know which value of z satisfy the previous equation so then we can do this:

$z=-0.842$

And if we solve for a we got

$a=500 -0.842*100=415.8$

So the value of height that separates the bottom 20% of data from the top 80% is 415.8.

8 0

3 years ago