MathDB
2017 COMC C1

Source:

October 12, 2018
Comc2017 COMC

Problem Statement

Source: 2017 Canadian Open Math Challenge, Problem C1 —-- For a positive integer nn, we define function P(n)P(n) to be the sum of the digits of nn plus the number of digits of nn. For example, P(45)=4+5+2=11P(45) = 4 + 5 + 2 = 11. (Note that the first digit of nn reading from left to right, cannot be 00). \qquad(a) Determine P(2017)P(2017). \qquad(b) Determine all numbers nn such that P(n)=4P(n) = 4. \qquad(c) Determine with an explanation whether there exists a number nn for which P(n)āˆ’P(n+1)>50P(n) - P(n + 1) > 50.
Back to ProblemsView on AoPS