1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
11Alexandr11 [23.1K]
3 years ago
13

Mrs. Smith's class is working on a variety of science experiments. Each

Mathematics
1 answer:
SVETLANKA909090 [29]3 years ago
8 0

Answer:

66

Step-by-step explanation:

If there are  <em>n</em>  students, then the number of pairs is \frac{n(n-1)}{2}.

With 12 students, \frac{12(12-1)}{2} = \frac{132}{2}=66 pairs can be formed.

The reason the formula works is this:  Each of the 12 students can be paired with 11 other students (no student is paired with him/her self).  But counting 12 x 11 = 132  counts each pair <u>twice</u>.  Example: student A can be paired with student B,..., student B can be paired with student A.  The pair was counted two times.

See the attached image that shows pairings of 5 students.  There are

5(5 - 1)/2 = 5(4)/2 = 10 pairs.

You might be interested in
E<br> Find the mode of the<br> data set:<br><br> 25,29, 22,19,20,29, 23, 29,<br> 19,31
Vesna [10]

Answer:

the mode is 29

Step-by-step explanation:

the mode is the number that appears most often in a set of data, thus making it 29

7 0
2 years ago
Read 2 more answers
What is 1+1 im srry im in kindergraden
hram777 [196]

Answer: its 2 sweetheart

Step-by-step explanation:

6 0
3 years ago
There are 12 red pens, 20 blue pens and 5 black pens in a bag. What is the probability that you will pick a black pen? Round
Vlada [557]

Answer:

The probability of getting a black pen from the bag is 13.5%.

Step-by-step explanation:

To determine the percentage probability that a black pen will be obtained from the bag, the following calculation must be performed:

12 + 20 + 5 = 37

37 = 100%

5 = X

(5 x 100) / 37 = X

500/37 = X

13.5 = X

Thus, it is determined that the totality of pens is 100%, and through a cross multiplication the percentage of the 5 black pens with respect to the total of pens is obtained.

Therefore, the probability of getting a black pen from the bag is 13.5%.

5 0
3 years ago
Solve for − ∣ x − 2 ∣ + 4 ≤ 0
MakcuM [25]

Answer:

x ≥ 6 or x ≤ -2

Step-by-step explanation:

- I x - 2 I + 4 ≤ 0

- I x - 2 I ≤ -4

I x - 2 I ≥ 4

x - 2 ≥ 4  or  x - 2 ≤ -4

x ≥ 6  or x ≤ -2

5 0
2 years ago
A company has two packaging machines in a unit, each with a different daily capacity. The capacity of machine 1 is defined by th
ollegr [7]

Total capacity = sum of the individual production capacities.

Here,

Total capacity = sum of f(m) = (m + 4)^2 + 100  and g(m) = (m + 12)^2 − 50.

Then f(m) + g(m) =  (m + 4)^2 + 100 + (m + 12)^2 − 50.

We must expand the binomial squares in order to combine like terms:

 m^2 + 8 m + 16 + 100

+m^2 + 24m + 144 - 50

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

Then f(m) + g(m) = 2m^2 + 32m + 160 + 50  

      f(m) + g(m)   = 2m^2 + 32m + 210, where m is the number of

                                minutes during which the two machines operate.

6 0
3 years ago
Other questions:
  • How to solve y=7/10x+4/5
    12·1 answer
  • Find the solutions of the systems -6x-2y=8 and 7x-2y=-5
    6·1 answer
  • Simply 40xcubedbcubed/64bsquaredx3
    15·1 answer
  • What is 18,157 rounded to the nearest thousand
    9·2 answers
  • Solve for x.<br><br> 3(3x - 1) + 2(3 - x) = 0
    14·2 answers
  • All paper money in the united states is the same size no matter what the value is paper money has an area of about 16.86 square
    8·1 answer
  • Can i please have some help​
    13·1 answer
  • Michelle's father deposited $1,000 into a savings account when she was born. The annual interest rate is
    13·1 answer
  • Simplify the following expression.
    14·1 answer
  • Which expressions are equivalent to 7(-3/4 x - 3)? Select 2 options.
    14·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!