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1 year ago

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If x% of four-digit numbers have a repeated digit (the repeated digits do not need to be adjacent), then what is x? Express your

answer as a decimal to the nearest tenth. 40 pts here!!

1 answer:

joja [24]1 year ago

8 0

Answer

It is a 4 digit number but 1 digit (exactly one digit) is repeated just once.

So 3 digits out of 10 have to be chosen.

There are 10C3 = 120 ways to do this.

say the digits chose are 5,6 and 9, they can be in any order and there are 3! possible orders =6 orders.

So so far that is 120*6=720 ways to get a 3 digit number where the digits are all different.

But we want a 4 digit number.

One digit has to be repeated there are 3 possibilities so that is 720*3 = 2160 posibilities.

But there are 4 postions that extra number can be put in. So that is 2160*4=8640 numbers

But I have double counted because 1434 is the same if I swap the 4s around so I have to halve this answer

8640/2 = 4320

So the number of favourable outcomes is 4320.

Altogether there are 10*10*10*10 = 10000 4 digit numbers (if they are allowed to start with 0)

so the prob of getting just one digit repeated once is 4320/10000 = 0.4320 = 43.2%

Do you understand now?

You will need to write your query on this thread but also send me a private message with the address of this thread attached. Otherwise I will not see it.

If you do have a query try to ask a specific question.

Anyway I hope that you understand

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Learning Task 3. Find the equation of the line. Do it in your notebook.

Wewaii [24]

Answer:

1) The equation of the line in slope-intercept form is $y = 5\cdot x +9$ . The equation of the line in standard form is $-5\cdot x + y = 9$ .

2) The equation of the line in slope-intercept form is $y = \frac{2}{5}\cdot x +\frac{14}{5}$ . The equation of the line in standard form is $-2\cdot x +5\cdot y = 14$ .

3) The equation of the line in slope-intercept form is $y = 3\cdot x +4$ . The equation of the line in standard form is $-3\cdot x +y = 4$ .

4) The equation of the line in slope-intercept form is $y = 2\cdot x + 6$ . The equation of the line in standard form is $-2\cdot x +y = 6$ .

5) The equation of the line in slope-intercept form is $y = \frac{5}{6}\cdot x -\frac{7}{6}$ . The equation of the line in standard from is $-5\cdot x + 6\cdot y = -7$ .

Step-by-step explanation:

1) We begin with the slope-intercept form and substitute all known values and calculate the y-intercept: ( $m = 5$ , $x = -1$ , $y = 4$ )

$4 = (5)\cdot (-1)+b$

$4 = -5 +b$

$b = 9$

The equation of the line in slope-intercept form is $y = 5\cdot x +9$ .

Then, we obtain the standard form by algebraic handling:

$-5\cdot x + y = 9$

The equation of the line in standard form is $-5\cdot x + y = 9$ .

2) We begin with a system of linear equations based on the slope-intercept form: ( $x_{1} = 3$ , $y_{1} = 4$ , $x_{2} = -2$ , $y_{2} = 2$ )

$3\cdot m + b = 4$ (Eq. 1)

$-2\cdot m + b = 2$ (Eq. 2)

From (Eq. 1), we find that:

$b = 4-3\cdot m$

And by substituting on (Eq. 2), we conclude that slope of the equation of the line is:

$-2\cdot m +4-3\cdot m = 2$

$-5\cdot m = -2$

$m = \frac{2}{5}$

And from (Eq. 1) we find that the y-Intercept is:

$b=4-3\cdot \left(\frac{2}{5} \right)$

$b = 4-\frac{6}{5}$

$b = \frac{14}{5}$

The equation of the line in slope-intercept form is $y = \frac{2}{5}\cdot x +\frac{14}{5}$ .

Then, we obtain the standard form by algebraic handling:

$-\frac{2}{5}\cdot x +y = \frac{14}{5}$

$-2\cdot x +5\cdot y = 14$

The equation of the line in standard form is $-2\cdot x +5\cdot y = 14$ .

3) By using the slope-intercept form, we obtain the equation of the line by direct substitution: ( $m = 3$ , $b = 4$ )

$y = 3\cdot x +4$

The equation of the line in slope-intercept form is $y = 3\cdot x +4$ .

Then, we obtain the standard form by algebraic handling:

$-3\cdot x +y = 4$

The equation of the line in standard form is $-3\cdot x +y = 4$ .

4) We begin with a system of linear equations based on the slope-intercept form: ( $x_{1} = -3$ , $y_{1} = 0$ , $x_{2} = 0$ , $y_{2} = 6$ )

$-3\cdot m + b = 0$ (Eq. 3)

$b = 6$ (Eq. 4)

By applying (Eq. 4) on (Eq. 3), we find that the slope of the equation of the line is:

$-3\cdot m+6 = 0$

$3\cdot m = 6$

$m = 2$

The equation of the line in slope-intercept form is $y = 2\cdot x + 6$ .

Then, we obtain the standard form by algebraic handling:

$-2\cdot x +y = 6$

The equation of the line in standard form is $-2\cdot x +y = 6$ .

5) We begin with a system of linear equations based on the slope-intercept form: ( $x_{1} = -1$ , $y_{1} = -2$ , $x_{2} = 5$ , $y_{2} = 3$ )

$-m+b = -2$ (Eq. 5)

$5\cdot m +b = 3$ (Eq. 6)

From (Eq. 5), we find that:

$b = -2+m$

And by substituting on (Eq. 6), we conclude that slope of the equation of the line is:

$5\cdot m -2+m = 3$

$6\cdot m = 5$

$m = \frac{5}{6}$

And from (Eq. 5) we find that the y-Intercept is:

$b = -2+\frac{5}{6}$

$b = -\frac{7}{6}$

The equation of the line in slope-intercept form is $y = \frac{5}{6}\cdot x -\frac{7}{6}$ .

Then, we obtain the standard form by algebraic handling:

$-\frac{5}{6}\cdot x +y =-\frac{7}{6}$

$-5\cdot x + 6\cdot y = -7$

The equation of the line in standard from is $-5\cdot x + 6\cdot y = -7$ .

6 0

1 year ago

The average age of doctors in a certain hospital is 45.0 years old. Suppose the distribution of ages is normal and has a standar

Ad libitum [116K]

Answer: 0.7619

Step-by-step explanation:

Given : Mean : $\mu=45.0$

Standard deviation : $\sigma =8.0$

Sample size : $n=9$

We assume that the variable is normally distributed.

The value of z-score is given by :-

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

a) For x= 46.9 years

$z=\dfrac{46.9-45.0}{\dfrac{8}{\sqrt{9}}}=0.7125$

The p-value : $P(z$

Hence, the probability that the average age of those doctors is less than 46.9 years =0.7619

8 0

2 years ago

16z+29z=pz−v solve for z

Dmitry [639]

16z + 29z = pz - v....for z
45z = pz - v
45z - pz = -v
z(45 - p) = -v
z = -v / (45 - p) <==

6 0

1 year ago

Read 2 more answers

A researcher wants to compare the effect of a new type of shampoo on hair condition. The researcher believes that men and women

cupoosta [38]

Answer:

This experiment has three factors (shampoo type, gender, whether hair is dyed)

Step-by-step explanation:

the researcher is trying to make a comparison between an old shampoo and a new on and also was gender sensitive as she considers their hair coloration too because it affects the result slightly.

8 0

1 year ago

The number 8/7 = 1.14285714285714 ... obviously has no exact representation in any decimal floating point system (beta = 10) wit

arlik [135]

Answer:

The answer to this question can be defined as follows:

Step-by-step explanation:

In the first point:

Yes, the Finite Floating Point Structures are considered Where $\beta = 7$

$\to \frac{8}{7}= (1.1)_7$

$\bold{= 1 \times 7^0 + 1 \times 7^{-1}}\\\\$

In the second point:

There is no device with a finite floating-point since the right side is

This equality never happens, then, with the rational numbers ( $\alpha_i$ and $\beta$ is rational).

5 0

2 years ago