I need some urgent help on this question.
It says we have to prove that
floor of(5*x)- 5* (floor of x ) <4.1
I have been struggling this problem from past goddamn 6 hours :| wth
You have $\displaystyle \lfloor 5x\rfloor \leq 5x $ and $\displaystyle \lfloor x\rfloor > x-1$, hence $\displaystyle \lfloor 5x\rfloor - 5\lfloor x\rfloor < 5x - 5(x-1)=5$. Moreover, $\displaystyle \lfloor 5x\rfloor - 5\lfloor x\rfloor$ is an integer, so that the previous inequality is equivalent to $\displaystyle \lfloor 5x\rfloor - 5\lfloor x\rfloor\leq 4$.