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3 years ago

if b =the number of blackbirds that flew away away which mathematical sentence expresse the information

Mathematics

1 answer:

Elis [28]3 years ago

3 0

X = total number of birds
b= blackbirds
x - b = number of birds left.
hope this helps

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A gem is cut in a kite shape. It is 6.2 millimeters wide at its widest point & 5 millimeters long. What is the area?

arlik [135]

Answer: $15.5\ mm^2$

Step-by-step explanation:

You can calculate the area of a kite with the following formula:

$A=\frac{d_1d_2 }{2}$

Where $d_1$ is the length of a diagonal and $d_2$ is the length of the other diagonal.

In this case, you can identify that:

$d_1=6.2\ mm\\d_2=5\ mm$

Therefore, the final step is to substitute the values into the formula.

Then, the area is:

$A=\frac{(6.2\ mm)(5\ mm)}{2}\\\\A=15.5\ mm^2$

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3 years ago

The regular price of a pair of sneakers is $80. They are on sale now for $50. What is the percent decrease in the price of sneak

Tamiku [17]

Answer:

62.5% decrease

Step-by-step explanation:

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3 years ago

If X denotes the number of heads in n tosses of a coin, what is the standard deviation of the random variable X? Does this stand

vfiekz [6]

Answer:

$\sigma=\sqrt{np(1-p)}=\sqrt{n*0.5(1-0.5)}=\frac{\sqrt{n}}{2}$

As we can see the deviation is proportional to the value of n and if n increase then the deviation increases too. So then the deviation would be larger when n gets larger.

Step-by-step explanation:

Previous concepts

The binomial distribution is a "DISCRETE probability distribution that summarizes the probability that a value will take one of two independent values under a given set of parameters. The assumptions for the binomial distribution are that there is only one outcome for each trial, each trial has the same probability of success, and each trial is mutually exclusive, or independent of each other".

The probability mass function for the Binomial distribution is given as:

$P(X)=(nCx)(p)^x (1-p)^{n-x}$

Where (nCx) means combinatory and it's given by this formula:

$nCx=\frac{n!}{(n-x)! x!}$

Solution to the problem

We can define the following random variable X ="Number of heads in n tosses of a coin".

We assume that the coin is fair and then $P(H)= 0.5$ for any trial so then we can model X with the following distribution:

$X \sim Bin (n, p=0.5)$

For this distribution the mean and variance are given by:

$E(X)=np=n*0.5=\frac{n}{2}$

$Var(X)= np(1-p) = n*0.5*(1-0.5) = 0.25 n = \frac{n}{4}$

And the deviation would be just the square root of the variance and we got:

$\sigma=\sqrt{np(1-p)}=\sqrt{n*0.5(1-0.5)}=\frac{\sqrt{n}}{2}$

Does this standard deviation get larger or smaller when n gets larger?

As we can see the deviation is proportional to the value of n and if n increase then the deviation increases too. So then the deviation would be larger when n gets larger.

3 0

3 years ago

laura earns 255 dollars by working 20 hours each week, write an equation to find how much laura earns per hour use h to represen

bogdanovich [222]

255÷20= 12.75
This is your answer

7 0

3 years ago

Read 2 more answers

50 points for this question

nekit [7.7K]

Answer:

50°