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Combination Replacement Calculator

Combinations with Replacement Formula:

\[ C(n,k) = \frac{(n + k - 1)!}{k!(n - 1)!} \]

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1. What is Combination with Replacement?

Combinations with replacement (or multiset combinations) is the number of ways to choose k elements from a set of n elements where order doesn't matter and elements can be chosen more than once.

2. How Does the Calculator Work?

The calculator uses the combinations with replacement formula:

\[ C(n,k) = \frac{(n + k - 1)!}{k!(n - 1)!} \]

Where:

Explanation: This formula accounts for selections where items can be repeated and order doesn't matter.

3. Importance of Combinations with Replacement

Details: This concept is crucial in probability, statistics, and combinatorics for problems involving selection with repetition, such as distributing identical items or sampling with replacement.

4. Using the Calculator

Tips: Enter positive integers for n (total items) and k (items to choose). The calculator will compute the number of possible combinations with replacement.

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between combinations and combinations with replacement?
A: Regular combinations don't allow repetition, while combinations with replacement do.

Q2: What are some real-world applications?
A: Used in probability problems, inventory management, and when counting possible outcomes where items can be repeated.

Q3: How does this differ from permutations with replacement?
A: Permutations consider order important, while combinations don't.

Q4: What's the largest numbers this calculator can handle?
A: Due to factorial growth, values above 170 may cause overflow issues.

Q5: Can this be used for probability calculations?
A: Yes, it's often used in probability to determine the number of possible outcomes.

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