Is there a short method?

\[\sum _{ r=1 }^{ 15 }{ { \left( -1 \right) }^{ r+1 }\left( \begin{matrix} 15 \\ r \end{matrix} \right) \left( \begin{matrix} 17r \\ 15 \end{matrix} \right) } =A\]

Find the second last digit of \(A\).


This question came in an exam. Please provide a solution which uses a short method.
×

Problem Loading...

Note Loading...

Set Loading...