Problem 10
(a) A teacher selects a team of three from a group of students. She also
selects a team of two (students can be in more than one team). The
teacher notices that there are twice as many ways of choosing the
team of three as there are the team of two. How many students are
in the group?
(b) For another group of students, there are three times as many teams
of three which can be selected as there are teams of two. How many
teams of three can be selected from this group?

Answers

Answer 1

Using the combination formula, it is found that:

a) There are 8 students in the group.b) 165 teams of three can be selected from this group.

---------------------------

The order in which the students are chosen is not important, which means that the combination formula is used to solve this question.

Combination formula:

is the number of different combinations of x objects from a set of n elements, given by the following formula.

[tex]C_{n,x} = \frac{n!}{x!(n-x)!}[/tex]

---------------------------

Question a:

3 students from a set of n, thus: [tex]C_{n,3}[/tex]2 students from a set of n, thus: [tex]C_{n,2}[/tex]

Twice as many ways to choose the teams of 3 than the teams of 2, thus:

[tex]C_{n,3} = 2C_{n,2}[/tex]

[tex]\frac{n!}{3!(n-3)!} = 2\frac{n!}{2!(n-2)!}[/tex]

We have to solve for n, thus:

[tex]2!n!(n-2)! = 2(3!)(n!)(n-3)![/tex]

[tex](n-2)! = 3!(n-3)![/tex]

From the factorial concept: [tex](n-2)! = (n-2)(n-3)![/tex], thus:

[tex](n-2)! = 3!(n-3)![/tex]

[tex](n-2)(n-3)! = 3!(n-3)![/tex]

[tex]n - 2 = 3![/tex]

[tex]n - 2 = 6[/tex]

[tex]n = 8[/tex]

There are 8 students in the group.

---------------------------

Question b:

First we have to find the total number of students, using the same logic as item a.

[tex]C_{n,3} = 2C_{n,2}[/tex]

[tex]\frac{n!}{3!(n-3)!} = 3\frac{n!}{2!(n-2)!}[/tex]

[tex]2!n!(n-2)! = 3n!3!(n-3)![/tex]

[tex]2(n-2)(n-3)! = 18(n-3)![/tex]

[tex]n - 2 = 9[/tex]

[tex]n = 11[/tex]

---------------------------

The number of teams of three is:

[tex]C_{11,3} = \frac{11!}{3!8!} = 165[/tex]

165 teams of three can be selected from this group.

A similar problem is given at https://brainly.com/question/23302762


Related Questions

Please solve both i will give brainliest!!! Love you in advance <3

Answers

the answer is 2/10(3a)

how to Calculate the value of the angles indicated by small letters

Answers

Answer:

all you need to do is to follow steps . you can also use trigonometric ratios to get your unknown angle or using cosine rule and sine rule.

You plan to cut a board into 3 pieces to repair part of a railing. You are going to cut the two ends of the board off into two equal pieces that are 3.1 feet long, if the remaining piece needs to be 2.27 times longer than the each of the first two cuts what length board should you buy? Round to the nearest tenth

Answers

Answer:

the answer might be 20

Step-by-step explanation:

first you add 3.1 to 3.1 to get 6.2

then you multiply 6.2 by 2.27

then you add the answer you get from that to 3.1+3.1 to get the final length ‍to be 20.274 and that would be 20 in the nearest tenth

Rey grew a tomato plant from seed. He measured its height
during the month of June. How much did it grow between
June 21 and June 28?

5 cm?
4 cm?
3 cm?

Answers

Answer:

3 cm

Step-by-step explanation:

Fimd the hcf of 144,384 and 432 by division method. ​

Answers

48..................

Please, someone help me with this task, I am stuck

Answers

Answer: the equation is y = -5x/6 - 2

Step-by-step explanation:

x1 = -6

y1 = 3

x2 = 6

y2 = -7

now

m(slope) = rise/run = (y2-y1)/(x2-x1)

   = (-7-3)/(6-(-6))

  =  -10/12

   = -5/6

now

y = mx+ b

-7 = m*6 + b

or, -7 = -5/6*6 + b

or, -7 = -5 + b

so, b = -2

now

y = mx +b

y = -5/6*x + (-2)

y = -5x/6 - 2

Answer:

y = -5/6 × x - 2 = -5x/6 - 2

Step-by-step explanation:

we have two marked points with seemingly integer coordinates for x and y.

the equation of a line is

y = a×x + b

now, we only need to put the x and y values pairs into this equation and calculate a and b.

P1 = (-6, 3)

P2 = (6, -7)

based on what I can see on the picture.

starting with P1

3 = a×-6 +b

b = 3 + a×6

then with P2

-7 = a×6 + b = a×6 + 3 + a×6 = a×12 + 3

-10 = a×12

a = -10/12 = -5/6

=>

b = 3 + a×6 = 3 + -5/6 × 6 = 3 - 5 = -2

so, the line equation is

y = -5/6 × x - 2 = -5x/6 - 2

What is the smallest integer greater than the square root of 325

Answers

Answer:

19

Step-by-step explanation:

√325 ≈ 18.02

The next greatest integer is 19.

If my answer is incorrect, pls correct me!

If you like my answer and explanation, mark me as brainliest!

-Chetan K

What is the difference between 34343 and 1212

Answers

Answer:

33131

Step-by-step explanation: 34343-1212= 33131

Hi! I'm happy to help!

To find the difference, means to use subtraction. So, to solve this, we need to subtract.

34343-1212=33131

The difference between 34343 and 1212 is 33131.

I hope this was helpful, keep learning! :D

can someone help me please?

Answers

Hi :)

15x^12/18x^2

Factor 3 out of 15 and 18

3(5x^12)/3(6x^2)

Divide

5x^10/6

Answer:

[tex] \frac{15 {x}^{12} }{18 {x}^{2} } \\ \frac{15}{18} \times \frac{ {x}^{12} }{ {x}^{2} } \\ \frac{5}{6} \times {x}^{12- 2} \\ \frac{5}{6} \times {x}^{10} \\ \frac{5 {x}^{10} }{6} [/tex]

An aircraft carrier left Hawaii traveling west seven hours before a container
ship. The container ship traveled in the opposite direction going 5 km/h slower
than the aircraft carrier for six hours after which time the ships were 540 km apart.
Find the aircraft carrier's speed.

Answers

Answer:

so speed of aircraft carrier is 30. thank you

The speed of an aircraft carrier is 30 km/h.

What is Speed?

speed is described as. the pace at which an object's location changes in any direction. Speed is defined as the distance traveled divided by the travel time. Speed is a scalar quantity because it just has a direction and no magnitude.

Given, An aircraft carrier left Hawaii traveling west seven hours before a container ship. The container ship traveled in the opposite direction going 5 km/h slower than the aircraft carrier.

Since,

Speed = distance/time

time is 13 hours, 7 hours before the container ship left then the 6 hours container traveled.

Let "s" be the speed of the aircraft carrier

=> d = 13s

Container ship:

time is 6 hours

speed is 5 km/h slower, so s-5

=> d = 6(s-5)

Since they are going in opposite directions, add up the distances to find how far apart they are

=> 13s + 6(s-5) = 540

Now solve for s-

=> 13s +6s -30 = 540

=> 19s = 570

=> s = 30

therefore, the Aircraft carrier was traveling at the speed of 30 km/h and the container ship at the speed of 25 km/h.

Learn more about speed here:

https://brainly.com/question/28224010

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What is the surface
area of a beach ball
with a diameter of 20
inches?

Answers

Step-by-step explanation:

diameter =20inches

radius =20/2=10 in

Surface area of sphere, A = 4πr²

π=3.14

area = 4×3.14×(10)²

area=1,256 in²

Divide 170 in the ratio 3.5 , 1.25 , 2.33 please show calculations.​

Answers

Answer:

84.04, 30.14 and 55.95

Step-by-step explanation:

First you add the ratios together then divide by 170 and mutliply each answer by the answer of 170 divided by the sum of 3.5, 1.25 and 2.33

Answer:

84.04, 30.14 and 55.95

Step-by-step explanation:

→ Add the ratios together

3.5 + 1.25 + 2.33 = 7.08

→ Divide the answer by 170

170 ÷ 7.08 = 24.01129944

→ Multiply the answer by 3.5 , 1.25 , 2.33

3.5 × 24.01129944 = 84.04

1.25 × 24.01129944 = 30.14

2.33 × 24.01129944 = 55.95

URGENT!! Please help me
Draw the answer on and explain if you can please
Thanks a lot!!

I already filled in the 12345 but I need help on the top row.​

Answers

Answer:

Step-by-step explanation:

Evaluate the expression, given functions f and h:  

f(x) = 3x − 1,

 

h(x) = −2x2 + 3x − 2.

f  

7

3

− h(−2)

Answer:

2.5 5 7.5 10 12.5

Step-by-step explanation:

b) 2.5*6=15

HELPPP MEE OUT PLZZZZZ

Answers

its 54 , they gave you one answer and you know its a right angle. You do 90 - 36 and get 54 :)

How do you find the slope of a line given the points ( -1 , -1 ) and ( 5 , -3 ) on the line?

Answers

Answer:

-1/3

Step-by-step explanation:

The formula for slope is [ y2-y1/x2-x1 ].

-3-(-1)/5-(-1)

-2/6

-1/3

Best of Luck!

Rewrite the following expressions as addition:

-25 + (-32) - 14

-14 - (-45) - 13

Answers

Answer:

-53

Step-by-step explanation:

-25-32-14-14+45-13

=53

Answer:

ANS IS -53

AS +45 &-45 WILL GET CANCELLED

AND -14-14-25 WILL GET ADDED

THAT IS -53

WHAT IS A COMPUTER??​

Answers

Answer:

A computer is an electronic device for storing and processing data, typically in binary form, according to instructions given to it in a variable program.

Answer:

a computer ia an electronic device which process raw data and gives meaningful information to the user

Pls help me sry for asking so much..

Answers

Answer:

Z = 3/2

Hope it helps!! :)

please help angles on a Cartesian plane

Answers

Answer:

a) 16/25

b)3/2

Step-by-step explanation:

all explaination is in picturw below

Sketch the graph of y=-4(x+4)^2+4 and identify the axis of symmetry.​

Answers

Answer: (-4,4) is the vertex.  The graph is symmetrical to the x = -4 line.

Step-by-step explanation:

Graph the equation using DESMOS.

Half a watermelon and a half pound of cherries cost $3.09. A whole watermelon and two pounds of cherries cost $8.16. Find the cost of each type of fruit. (Find the cost of cherries per pound)

Answers

Answer:

each watermelon=$1.98, each pound of cherry=$4.2

Step-by-step explanation:

all step by step explaination is in picture.

Determine the vertical distance and horizontal distance of P(-2,1) and Q(8,7).

Answers

Answer:

5.830952 should be the answer  

Step-by-step explanation:

Plz help with these 2 questions WILL GIVE BRAINLIEST!!

Answers

Answer:

<ALS - <2 = <1

< LDA + <ADE = 180  degrees

Step-by-step explanation:

<ALS = <1+<2

<ALS - <2 = <1

< LDA + <ADE = 180  degrees since it forms a straight line

Eighth grade
>
A.2 Divisibility rules
Is 932,920 divisible by 4?
Yes or no

Answers

Answer:

Yes.

Brainliest, please!

Step-by-step explanation:

If we try to divide 932,920 by 4, we get 233,230, which is a whole number.

Answer:

Step-by-step explanation:

Yes!

Done without a calculator. Just look at the last 2 digits. 20 is divisible by 4 so the whole number is. Now you can check it with your calculator.

932920 / 4 = 233230

ASAP PLS

1. Using the figure below to answer the question. If the sector (APB) has an area of 7pi and m<APB = 44°, find the radius length for circle P. (answer choices are 6.35, 9.27, 7.57, and 9.7)​

Answers

Answer:

7.57

Step-by-step explanation:

the area = 44/360 × π × r²

7 π = 44/360 × π× r²

eliminate π

7 = 44/360 x r²

r² = 7× 360/44

r² = 57.27

r =√57.27 = 7.57

13 x − y 13 x - y given that x = 11 x = 11 and y = 18 y = 18

Answers

Answer:

125

Brainliest, please!

Step-by-step explanation:

13x - y

x = 11, y = 18

13(11) - 18

143 - 18

125

Answer:

125

Step-by-step explanation:

13x - y

Substituting x = 11 and y = 18,

=> 13(11) - 18

=> 143 - 18

=> 125

How would you write the expression "6 is less than a number tripled?"

Answers

Answer:

3q

Step-by-step explanation:

i think

Answer:

6< 3x

[where 3x = a number tripled]

What is 6 tenths, 2 hundredths, 8 thousandths in standard form?

A.0.0628 B.0.628 C.6.28 D.628

Answers

Answer:

B: 0.628

Step-by-step explanation:

Place value rules.

The value of each digit in a number is known as the place value. The number that has 6 tenths, 2 hundredths, and 8 thousandths can be written in the standard form as 0.628. The correct option is B.

What is the place value of a digit in a number?

The value of each digit in a number is known as the place value. The 5 in 350, for example, represents 5 tens, or 50, whereas the 5 in 5,006 represents 5 thousand, or 5,000. It is critical that children that while a digit can be the same, its value is determined by its position in the number.

Identification of the place value of a digit in a number:

The place values on the left of the decimal point start as ones, tens, hundreds, and so on.The place value on the right of the decimal point starts from the point and goes to the right as tenths, hundredths, and so onThe tens mean multiply by 10The tenth means the tenth part of that digit which is that digit divided by 10

Given 6 tenths, 2 hundredths, 8 thousandths, this can be written in the standard form as,

Standard form = 0.6 + 0.02 + 0.008 = 0.628

Hence, the number that has 6 tenths, 2 hundredths, and 8 thousandths can be written in the standard form as 0.628.

Learn more about the Place Value here:

https://brainly.com/question/27734142

#SPJ2

What is 0.278 rounded to the nearest tenth?

Answers

Answer:

0.3

Step-by-step explanation:

If you like to round 0.278 to the nearest tenth, leaving only one number after the decimal point, then you have come to the right post

Therefore the answer is 0.3

Hope you got it

If you have any question just ask me

If you think this is the best answer please mark me as BRAINLIEST

Look at photo for question ?​

Answers

Answer:

1/3n - 3<6

n < 27

Step-by-step explanation:

1/3n - 3<6

Add 3 to each side

1/3n -3+3<6+3

1/3 n <9

Multiply by 3

1/3n *3 < 9*3

n < 27

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