Can someone help me out

Given:

Total number of people = 10

To find:

The number of ways in which 10 people can be divided into three groups of 2, 3, and 5 people respectively.

Solution:

We know that the number of ways to select r items form n times is:

[tex]^nC_r=\dfrac{n!}{r!(n-r)!}[/tex]

The number of ways to select 2 people from 10 is [tex]^{10}C_2[/tex].

The number of remaining people is [tex]10-2=8[/tex].

The number of ways to select 3 people from 8 is [tex]^{8}C_3[/tex].

The number of remaining people is [tex]8-3=5[/tex].

The number of ways to select 5 people from 5 is [tex]^{5}C_5[/tex].

Now, the total number of ways is:

[tex]Total=^{10}C_2\cdot ^{8}C_3\cdot ^{5}C_5[/tex]

[tex]Total=\dfrac{10!}{2!(10-2)!}\cdot \dfrac{8!}{3!(8-3)!}\cdot \dfrac{5!}{5!(5-5)!}[/tex]

[tex]Total=\dfrac{10\times 9\times 8!}{2\times 1\times 8!}\cdot \dfrac{8\times 7\times 6\times 5!}{3\times 2\times 1\times 5!}\cdot 1[/tex]

[tex]Total=45\cdot 56\cdot 1[/tex]

[tex]Total=2520[/tex]

Therefore, the total number of ways is 2520 to divide 10 people into three groups of 2, 3, and 5 people respectively.

It looks like you have to find the value of the sum,

[tex]C = \displaystyle \frac1{21\times22\times23} + \frac1{22\times23\times24} + \cdots + \frac1{200\times201\times202}[/tex]

so that the n-th term in the sum is

[tex]\dfrac1{(21+(n-1))\times(21+n)\times(21+(n+1))} = \dfrac1{(n+20)(n+21)(n+22)}[/tex]

for 1 ≤ n ≤ 180.

We can then write the sum as

[tex]\displaystyle C = \sum_{n=1}^{180} \frac1{(n+20)(n+21)(n+22)}[/tex]

Break up the summand into partial fractions:

[tex]\dfrac1{(n+20)(n+21)(n+22)} = \dfrac a{n+20} + \dfrac b{n+21} + \dfrac c{n+22}[/tex]

Combine the fractions into one with a common denominator and set the numerators equal to one another:

[tex]1 = a(n+21)(n+22) + b(n+20)(n+22) + c(n+20)(n+21)[/tex]

Expand the right side and collect terms with the same power of n :

[tex]1 = a(n^2+43n+462)+b(n^2+42n+440) + c(n^2+41n + 420) \\\\ 1 = (a+b+c)n^2 + (43a+42b+41c)n + 462a+440b+420c[/tex]

Then

a + b + c = 0

43a + 42b + 41c = 0

462a + 440b + 420c = 1

==>   a = 1/2, b = -1, c = 1/2

Now our sum is

[tex]\displaystyle C = \sum_{n=1}^{180} \left(\frac1{2(n+20)}-\frac1{n+21}+\frac1{2(n+22)}\right)[/tex]

which is a telescoping sum. If we write out the first and last few terms, we have

C = 1/(2×21) - 1/22 + 1/(2×23)

… … + 1/(2×22) - 1/23 + 1/(2×24)

… … + 1/(2×23) - 1/24 + 1/(2×25)

… … + 1/(2×24) - 1/25 + 1/(2×26)

… … + … - … + …

… … + 1/(2×198) - 1/199 + 1/(2×200)

… … + 1/(2×199) - 1/200 + 1/(2×201)

… … + 1/(2×200) - 1/201 + 1/(2×202)

Notice the diagonal pattern of underlined and bolded terms that add up to zero (e.g. 1/(2×23) - 1/23 + 1/(2×23) = 1/23 - 1/23 = 0). So, like a telescope, the sum collapses down to a simple sum of just six terms,

C = 1/(2×21) - 1/22 + 1/(2×22) + 1/(2×201) - 1/201 + 1/(2×202)

which we simplify further to

C = 1/42 - 1/44 - 1/402 + 1/404

C = 1,115/1,042,118 ≈ 0.00106994

Answer:

25%

Step-by-step explanation:

1 ÷ 4 = 0.25

0.25 x 100 = 25 = 25%

Answer:

Step-by-step explanation:

You need to find the model for this situation using the points given. If you are given 13 mg immediately, the coordinate point for that is (0, 13), where the x coordinate is the time in minutes and the y coordinate is the amount of dye in mg.

If after 12 minutes, 4.75 mg remain, the coordinate point for that is (12, 4.75). Just so you know, the time unit always goes in for x, never for y.

Now that we have these coordinates we are going to use them as a system and find the model. Begin with the point (0, 13) in

[tex]A=a(b)^t[/tex] where A is the amount left in the body, a is the initial amount injected, b is the rate at which it decays, and t is the time in minutes. Plug in the first set of coordinates:

[tex]13=a(b)^0[/tex] and since anything raised to the power of 0 is equal to 1, we have

13 = a. Now we can use that and write another equation with the other set of coordinates to solve for b:

[tex]4.75=13(b)^{12}[/tex] and divide both sides by 13 (don't round anything yet) to get

.3653846154 = b¹². Now take the 12th root of both sides (you need a scientific calculator for this) to get that

b = .9195228407  Yikes.

Now for the model, using the fact that a = 13 and b = .9195228407:

[tex]A=13(.9195228407)^t[/tex]  

We are told that the amount that we are allowed to leave with still remaining in our system cannot be more than 2 mg, so we sub in a 2 for A:

[tex]2=13(.9195228407)^t[/tex] and begin by dividing away 13 to get

[tex].1538461538=.9195228407^t[/tex]  Take the natural log of both sides, which allows us to bring the t out front:

ln(.1538461538) = t ln(.9195228407) and finally divide by ln(.9195228407) to get

t = 22.3 minutes

Answer:

L={∅}

Step-by-step explanation:

Answer:

From left to right it's square square rectangle.

Answer:

It's D:5.3

Step-by-step explanation:

√28 =5.29

Round off therefore is 5.3

Answer:

Wdym? that is fraction form, but if you ment decimal form; it is .7777 repeating and .25

Step-by-step explanation:

Answer:

(0+a)/2 , (0+a)/2

= (a/2, a/2)

Answered by GAUTHMATH

Answer:

solving for x

Step-by-step explanation:

4 or -6

Answer:

x = 4

Step-by-step explanation:

Those absolute value signs are a trick, well at least for this problem. Solve it how you usually would. However, if +2 was -2 or +/-2, then you would need to pay attention. Basically, those signs make the whole equation incased positive no matter what.

Answer:

(a-b)(b-c)(a-c)

Step-by-step explanation:

a^2(b - c) + b^2(c-a) + c^2(a - b)

= a^2b - a^2c + b^2c - b^2a + c^2a-c^2b

=a^2b - b^2a - a^2c + b^2c + c^2a -c^2b

= ab(a - b) - c(a^2 - b^2) +c^2(a - b)

=ab(a - b) -c(a - b)(a + b) +c^2(a - b)

=(a - b)(ab - c(a + b) +c^2)

=(a - b)(ab - cb -ca + c^2)

= (a - b)(b(a-c) -c(a-c))

=(a-b)(b-c)(a-c)

Answer:

4i

Step-by-step explanation:

apply (a+b)^2 formula

2x - 22 < -8

Add 22 to both sides

2x < 14

Divide both sides by 2

X < 7

Answer:

[tex]2x-22<-8[/tex]

Add 22 to both sides

[tex]2x-22+22<-8+22[/tex]

[tex]2x<14[/tex]

Divide both sides by 2

[tex]\frac{2x}{2}<\frac{14}{2}[/tex]

[tex]x<7[/tex]

OAmalOHopeO

Answer:

Option C

X>1

Step-by-step explanation:

x-7>-6

x>-6+7

x>1

Please Mark me brainliest

Answer:

C

Step-by-step explanation:

x - 7 > -6

x > -6 + 7

x > 1

• We change the inequality sign if we multiply or divide a negative number from both sides. But since it’s positive and we added it we won’t change the inequality sign.

Answer:  2/1  (Choice D)

Explanation:

He flipped the coin 39 times, of which 26 heads came up. That must mean 39-26 = 13 tails came up.

The ratio of heads to tails is 26/13 = 2/1

We can write that as 2:1 to mean similar notation. The key is that we list heads first since the phrasing is "ratio of heads to tails", where heads is listed first. If you had tails first, then it would flip to 1/2 aka 1:2

Answer:

1. D

2.C

3. E

4.A

Step-by-step explanation:

the guy above or below me is incorrect.

2)10,290

105

98

10290

(3y-2z) (3y+2z)

3y(3y+2z)-2z(3y+2z)

9y2+6yz-2z(3y+2z)

9y2+6yz-6yz-4z2

9y2-4z2

Answer:

[×1] +16=10

×=10-16

×=-6

Answer:

x=5 and x=-5

Step-by-step explanation:

First subtract 16 from both sides.

Then solve for x+1=6 and x+1=-6

you answer should be x=5 and x=-5

Answer:

. .

Step-by-step explanation:

x^2-9x√x-12

solve by using formula (a+b)^2 and open the brackets

Answer:

3.375 cm^2

Step-by-step explanation:

The area of a parallelogram is given by

A = bh  where b is the base and h is the height

A = 2.25 * 1.5

A =3.375 cm^2

Area = length x height

Area = 2.25 x 1.5

Area = 3.375 cm^2

Answer:

2304 in^3

Step-by-step explanation:

12×12×6+8×10×18

=864+1440

=2304

x > 0.8

x > -2

hope it helps :)

The solution of the given inequalities will be x > 0.8 and x < -2.

When two expressions are connected by a sign like "not equal to," "greater than," or "less than," it is said to be inequitable. The inequality shows the greater than and less than relation between variables and the numbers.

Given inequalities are x-0.8>0, and -5x<10. the inequalities will be solved as:-

x-0.8>0

x > 0.8

-5x<10

Take -5 to the right side and divide 10 by -5 and solve further.

x < -10 / 5

x < -2

Therefore, the solution of the given inequalities will be x > 0.8 and x < -2.

To know more about inequality follow

https://brainly.com/question/24372553

#SPJ5

Answer:

Step-by-step explanation:

1) The smaller sticks will range in length from almost 0 unit up to a maximum of 0.5 unit, with each length equally possible.

Therefore, the average length will be about (0 + 0.5)/2 = 0.25 unit

2)If you assume that each break in the stick is uniformly distributed along the length of the stick and is independent of the location of the other break, then the odds are 25% that you will be able to form a triangle with the 3 pieces.

We'll call the length of the stick 1, so each break can occur at a position in the interval [0,1]. Let x and y represent the two breaks. Then we can look at the area of the region in the square bounded x=0, x=1, y=0, y=1, which represents combinations of x and y, for which we can form a triangle. Since the area of the whole square is 1, the area of the region inside is our probability.

If y>x, then the lengths of the pieces are x, y-x, and 1-y.

The triangle inequality must hold for each combination of edges.

for y>x ...

x+y−x≥1−y

x+1−y≥y−x

y−x+1−y≥x

these simplify to...

for y>x ...

y≥1/2

x+1/2≥y

x≤1/2

If we cut our 1x1 square into two triangles along the line x=y,

then the region in the upper triangle which satisfies the inequalities above forms a smaller triangle which connects the midpoints of the upper triangle.

The lower triangle (x>y), is just a reflection about x=y of the upper triangle, so together, the entire region looks like a bow-tie at a 45 degree angle.

This region takes up 25% of the square, so the probability that you can form a triangle is 25%

3/7×4/7= (3×4)/(7×7)= 12/49

Answer:

12/49

Step-by-step explanation:

Hi! To start off, I'm going to multiply our numerators, and then our denominators.

3 × 4 = 12

7 × 7 = 49

Usually, if this fraction was not simplified (but it is) we would simplify it (ex. 2/4 to 1/2).

Hope this Helps! :)

Have any questions? Ask below in the comments and I will try my best to answer.

-SGO

Answer:

y - 4 = 1/3 (x + 2)

3 y - 12 = x + 2

3y = x + 14

y = x / 3 + 14 / 3

Using y = m x + b    as the equation for a standard line

We see that equation represents a line with slope of 1/3

When x = 0  the y-intercept is 14 /3

Answer: 1884 cm³

Step-by-step explanation:

cylinder volume = π · r² · h

π · r² · h = 3.14 · 5² · 24 = 3.14 · 25 · 24 = 1884 cm³

Answer:

x = 126

Step-by-step explanation:

The angles are complementary which means they sum to 180

x+54 =180

x = 180-54

x = 126

Answer:

5

Step-by-step explanation:

VU = VT because they are on two diagonals that intersect at the midpoint

Answer:

384 square units

Step-by-step explanation:

Square prism = Cube

Formula for finding the surface area of a cube = L x L (6)

Surface area = 8 x 8 (6)

Surface area = 64(6)

Surface area = 384 square units

Answer:

384 units squared

Step-by-step explanation:

Square 8 and then multiply by 6.