Problem #PRU-79473

Problems Methods Pigeonhole principle Pigeonhole principle (other) Algebra and arithmetic Algebraic inequalities and systems of inequalities Quadratic inequalites (several variables)

Problem

The numbers \(a_1, a_2, \dots , a_{1985}\) are the numbers \(1, 2, \dots , 1985\) rearranged in some order. Each number \(a_k\) is multiplied by its number \(k\), and then the largest number is chosen among the resulting 1985 products. Prove that it is not less than \(993^2\).