Exercise · ZW-BINOMIAL-COEFFICIENT-006 · ★★☆ Intermediate
Compute \(\dbinom{20}{18}\).
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- B. 190
Explanation
\(\dbinom{20}{18}=\dbinom{20}{2}=\dfrac{20\cdot 19}{2}=190\). The value \(380\) is \(P(20,2)\).
Review the concept: Binomial coefficient
The binomial coefficient \(\binom{n}{k}\), for integers \(0\le k\le n\), is the number of \(k\)-element subsets of a set with \(n\) elements.
\[\binom{n}{k}=\frac{n!}{k!\,(n-k)!}\]
More practice problems: binomial coefficient
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- ZW-BINOMIAL-COEFFICIENT-007 Which expression equals dbinomnk for 0≤ k≤ n?
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