There is a blank ruler of $X$ units. You are going to set $9$ marks on this ruler so that you will be able to measure all integer values from $1$ to $X$ units with only one measurement.
What is the maximum value $X$ can take?
For example: if this problem was asked for $3$ marks, the answer would be $9$ by marking $1$,$2$ and $6$ units on the ruler.
Source: 2006 Puzzleup