<h3>
Answer: 28</h3>
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Explanation:
Method 1
Imagine a table with 8 rows and 8 columns to represent all possible match-ups. You can actually draw out this table or just think of it as a thought experiment.
There are 8*8 = 64 entries in the table. Along the northwest diagonal, we have each team pair up with itself. This is of course silly and impossible. We cross off this entire diagonal so we drop to 64-8 = 56 entries.
Then notice that the lower left corner is a mirror copy of the upper right corner. A match-up like AB is the same as BA. So we must divide by 2 to get 56/2 = 28 different matches.
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Method 2
There are 8 selections for the first slot, and 8-1 = 7 selections for the second slot. We have 8*7 = 56 permutations and 56/2 = 28 combinations.
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Method 3
Use the nCr combination formula with n = 8 and r = 2

There are 28 combinations possible. Order doesn't matter (eg: match-up AB is the same as match-up BA).
Notice how the (8*7)/2 expression is part of the steps shown above in the nCr formula.
Y+5=-11
-5 -5
Y= -16
Answer:-16
Answer:
D
Step-by-step explanation:
Firstly let's see definition of Rational numbers ,
<u>Rational</u><u> numbers</u><u> </u><u>:</u><u>-</u><u> </u>
- The number in the form of p/ q where p and q are integers and q is not equal to zero is called a Rational number .
From the options , look at option D ,its
→ √400
→ √{20²}
→ 20
<h3>
Hence option D is correct.</h3>
Answer:
Let's imagine the image of the zoo.
The diameter is basically the length of the circle.
The penguin swam the radius.
To find the radius, we need to divide the diameter by 2.
The diameter is 20 meters.
20
2 = 10 meters.
2 x pi x 10 = 62.83185307
62.83185307/2 = 31.41592654
Answer = 31.41592654