Math Problem Statement

Compute C(5,2) (The number of ways to choose 2 objects from 5)

Solution

To compute C(5,2)C(5, 2), which represents the number of ways to choose 2 objects from 5 (also known as a combination), we use the formula for combinations:

C(n,r)=n!r!(nr)!C(n, r) = \frac{n!}{r!(n - r)!}

For C(5,2)C(5, 2), where n=5n = 5 and r=2r = 2:

C(5,2)=5!2!(52)!=5!2!3!C(5, 2) = \frac{5!}{2!(5 - 2)!} = \frac{5!}{2!3!}

Now, calculate the factorials:

5!=5×4×3×2×1=1205! = 5 \times 4 \times 3 \times 2 \times 1 = 120 2!=2×1=22! = 2 \times 1 = 2 3!=3×2×1=63! = 3 \times 2 \times 1 = 6

Now substitute these into the formula:

C(5,2)=1202×6=12012=10C(5, 2) = \frac{120}{2 \times 6} = \frac{120}{12} = 10

So, C(5,2)=10C(5, 2) = 10.

Do you want further explanation or examples? Feel free to ask!

Here are 5 related questions:

  1. How do you calculate the number of ways to choose 3 objects from 5?
  2. What is the difference between combinations and permutations?
  3. How does the formula for combinations change for larger values of nn and rr?
  4. How do combinations apply to probability problems?
  5. What are some real-world examples of using combinations?

Tip: Remember, the formula for combinations involves dividing by the factorials to account for overcounting of equivalent selections.

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Combinations
Factorials
Permutations

Formulas

C(n, r) = n! / (r!(n - r)!)

Theorems

Combination formula

Suitable Grade Level

Grades 7-9