MathDB
Spring 2020 Team Round Problem 4

Source:

August 22, 2020

Problem Statement

Suppose there are nn ordered pairs of positive integers (ai,bi)(a_i,b_i) such that ai+bi=2020a_i+b_i=2020 and aibia_ib_i is a multiple of 20202020, where 1in1\le i \le n. Compute the sum i=1nai+bi.\sum_{i=1}^{n} a_i+b_i.