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
Factorials
Struggling with Precalculus?
Join thousands of students who trust us to help them ace their exams!Watch the first videoMultiple Choice
Evaluate the expression.
12!⋅4!16!
A
0
B
1
C
1,820
D
43,680

1
Understand that the expression \( \frac{16!}{12! \cdot 4!} \) is a combination formula, specifically \( \binom{16}{4} \), which represents the number of ways to choose 4 items from 16 without regard to order.
Recall the formula for combinations: \( \binom{n}{r} = \frac{n!}{r!(n-r)!} \). In this case, \( n = 16 \) and \( r = 4 \).
Substitute the values into the combination formula: \( \binom{16}{4} = \frac{16!}{4!(16-4)!} = \frac{16!}{4! \cdot 12!} \).
Simplify the factorial expression by canceling out the common terms in the numerator and the denominator. This involves recognizing that \( 16! = 16 \times 15 \times 14 \times 13 \times 12! \), allowing \( 12! \) to cancel out.
Calculate the remaining product in the numerator: \( 16 \times 15 \times 14 \times 13 \) and divide by \( 4! = 4 \times 3 \times 2 \times 1 \) to find the number of combinations.
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