Table of contents
- 0. Fundamental Concepts of Algebra3h 29m
- 1. Equations and Inequalities3h 27m
- 2. Graphs1h 43m
- 3. Functions & Graphs2h 17m
- 4. Polynomial Functions1h 54m
- 5. Rational Functions1h 23m
- 6. Exponential and Logarithmic Functions2h 28m
- 7. Measuring Angles40m
- 8. Trigonometric Functions on Right Triangles2h 5m
- 9. Unit Circle1h 19m
- 10. Graphing Trigonometric Functions1h 19m
- 11. Inverse Trigonometric Functions and Basic Trig Equations1h 41m
- 12. Trigonometric Identities 2h 34m
- 13. Non-Right Triangles1h 38m
- 14. Vectors2h 25m
- 15. Polar Equations2h 5m
- 16. Parametric Equations1h 6m
- 17. Graphing Complex Numbers1h 7m
- 18. Systems of Equations and Matrices3h 6m
- 19. Conic Sections2h 36m
- 20. Sequences, Series & Induction1h 15m
- 21. Combinatorics and Probability1h 45m
- 22. Limits & Continuity1h 49m
- 23. Intro to Derivatives & Area Under the Curve2h 9m
21. Combinatorics and Probability
Combinatorics
Struggling with Precalculus?
Join thousands of students who trust us to help them ace their exams!Watch the first videoMultiple Choice
How many ways are there to arrange the letters in the word CALCULUS?
A
40,320
B
5,040
C
720
D
6

1
Identify the total number of letters in the word 'CALCULUS'. There are 8 letters.
Determine if there are any repeated letters. In 'CALCULUS', the letter 'C' appears twice, and the letter 'L' appears twice.
Use the formula for permutations of a multiset: \( \frac{n!}{n_1! \times n_2! \times \ldots \times n_k!} \), where \( n \) is the total number of letters, and \( n_1, n_2, \ldots, n_k \) are the frequencies of the repeated letters.
Substitute the values into the formula: \( \frac{8!}{2! \times 2!} \). Calculate \( 8! \) for the total permutations of the letters, and divide by the factorials of the repeated letters.
Simplify the expression to find the number of unique arrangements of the letters in 'CALCULUS'.
Watch next
Master Fundamental Counting Principle with a bite sized video explanation from Patrick
Start learning