Could someone solve this problem?

"Water depth is $\displaystyle x$. Water volume in vassel is calculated by

$\displaystyle {V}\left(x\right)=\frac{\pi}{3}\left(30x^2-x^3\right)$ while $\displaystyle 0 \leq x \leq 30$

It was measured that depth is 9cm.

While functions $\displaystyle V(x)$ alteration converting to differential, value what maximum deviancy may be done while calculating water volume, if it's depth was measured at 1mm precision."

Similar problem is supposed to be on exam, but I don't get it at all

Do I need to count remanant member here? (well... $\displaystyle Rn\left(x\right)=f\left(x\right)-Pn\left(x\right)$?)