can someone help me??!

I have this problem..

if $\displaystyle x(t)^{'} $ is a nonnegative and decreasing function and

$\displaystyle x(t) $ is a positive and nondecreasing

so..

$\displaystyle \frac{x^{'}(t)}{x(t)}\leqslant \frac{1}{t}$ for all $\displaystyle t\geqslant b $ ??!

I tried to prove this problem but at this step

$\displaystyle x(t)-x(b)\geqslant(t-b)x(t)^{'} $

I don't know how to get the rest of proof from this step..

can someone help me to get the rest of proof??

thanks for any help