Counting & ProbabilitySuperchallengeBinomial Theorem, Pascal & Combinatorial Identities ShareBinomial Theorem, Pascal & Combinatorial Identities · Superchallenge problemEvaluate ∑k=220(k2)2\displaystyle\sum_{k=2}^{20}\binom{k}{2}^{2}k=2∑20(2k)2.Check Show answer Walk through it step by step Practice more like this Review this concept