Let's try to find the solution to Duke Math Meet 2008 Problem 8. This question is from the individual round of that meet. Problem: Duke Math Meet 2008 Problem 8 Find the last two digits of $ \sum_{k=1}^{2008} k {{2008}\choose{k}} $ Discussion: $ (1+x)^n = \sum_{k=0}^{n} {{n}\choose{k}}x^k $ We differentiate both sides to have $ […]