Only approximately 1060510^{605} cases

Algebra Level 3

The numbers 1,2,3,...,2017,20181,2,3,...,2017,2018 are divided into 2 groups:

a1<a2<<a1009andb1>b2>>b1009.a_1<a_2<\cdots<a_{1009}\qquad \text{and} \qquad b_1>b_2>\cdots>b_{1009}.

What is the sum of all possible values of a1b1+a2b2++a1009b1009?|a_1-b_1|+|a_2-b_2|+\cdots+|a_{1009}-b_{1009}|?

×

Problem Loading...

Note Loading...

Set Loading...