On her coffee table, Sharon has a pile of 7 magazines. She plans to get through 2 of them over the weekend. How many sequences of 2 magazines are possible?
Question
On her coffee table, Sharon has a pile of 7 magazines. She plans to get through 2 of them over the weekend. How many sequences of 2 magazines are possible?
Solution
The problem can be solved using the concept of combinations in mathematics.
A combination is a selection of items where order does not matter. In this case, Sharon can choose 2 magazines out of 7 in any order.
The formula for combinations is:
C(n, r) = n! / [r!(n-r)!]
where:
- n is the total number of items,
- r is the number of items to choose,
- "!" denotes factorial, which is the product of all positive integers up to that number.
Substituting the given values into the formula:
C(7, 2) = 7! / [2!(7-2)!]
This simplifies to:
C(7, 2) = (7654321) / [(21)(54321)]
After canceling out the common factors, we get:
C(7, 2) = (76) / (21) = 21
So, there are 21 different sequences of 2 magazines that Sharon can choose from.
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