MathDB
[x/10]=[x/11]+1

Source: I - Rioplatense 1990 L3 P1

September 19, 2022
floor functionalgebradiophantine

Problem Statement

How many positive integer solutions does the equation have x10=x11+1?\left\lfloor\frac{x}{10}\right\rfloor= \left\lfloor\frac{x}{11}\right\rfloor + 1? (x\lfloor x \rfloor denotes the integer part of xx, for example 2=2\lfloor 2\rfloor = 2, π=3\lfloor \pi\rfloor = 3, 2=1\lfloor \sqrt2 \rfloor =1)