MathDB
2023 Fall Theme p1B

Source:

December 23, 2023
2023FAlLthemeCombo

Problem Statement

Evaluate (60)+(61)+(64)+(63)+(64)+(65)+(66)\dbinom{6}{0}+\dbinom{6}{1}+\dbinom{6}{4}+\dbinom{6}{3}+\dbinom{6}{4}+\dbinom{6}{5}+\dbinom{6}{6}
Proposed by Jonathan Liu
Solution. 64\boxed{64} We have that (64)=(62)\dbinom{6}{4}=\dbinom{6}{2}, so n=06(6n)=26=64.\displaystyle\sum_{n=0}^{6} \dbinom{6}{n}=2^6=\boxed{64}.