Answer:
66
Step-by-step explanation:
If there are <em>n</em> students, then the number of pairs is
.
With 12 students,
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.
Answer:
He would need 42 cm *or 14cm
Step-by-step explanation:
28/4 is 7
that means that he used 7 cm of tape per present
6 x 7 is 42
that means that he would need 42 cm of tape
4 to 28
6 to 42
*If he already has 4 presents done and he needs to 2 more present then he would need 14 cm, 2 x 7 is 14

This can be considered as a very easy Question where you have to find the value of √85 and √86 upto 2 decimal places then we could find it easily.
Let's start!
Value of √85=9.21
Value of √86=9.27
Now it is obvious that 9.25 lies between √85 and √86.

What are rational no.?
Any pair of numbers which is in the form of p/q where p and q are integers and p and q are co-prime is called rational number.
Answer:

Step-by-step explanation:
