<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.
Answer:
$40 per week
Step-by-step explanation:
Step one:
Given data
the initial amount is = $100
the total amount= $500
let the number of weeks be x
Step two:
The expression for the scenario is

From the expression above, the rate of the change is $40 per week.
this means that in every week the account will be increased by $40
Assuming that there are plus signs between the 6, 2, and 9 the answer is 21x+20
Answer:
Yes.
Step-by-step explanation:
We have given the price of apple per kilogram.
Hence, price of total apples is equal to the product of number of apples and price per kilogram of apple.