RIOPLATENSE 1990 Problem 1

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