\[\boxed{\text{27\ (27).}\text{\ }\text{Еуроки\ -\ ДЗ\ без\ мороки}}\]
\[p = \left\{ \begin{matrix} 2t + 20;\ \ \ \ \ \ \ \ \ \ \ \ \ \ 0 \leq t < 40 \\ 100;\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ 40 \leq t \leq 60 \\ - \frac{2}{3}t + 140;\ \ 60 < t \leq 150 \\ \end{matrix} \right.\ \]
\[p(20) = 2 \cdot 20 + 20 = 60;\]
\[p(40) = 100;\]
\[p(50) = 100;\]
\[p(60) = 100;\]
\[p(90) = - \frac{2}{3} \cdot 90 + 140 = 80.\]
\[На\ промежутке\ \lbrack 0;40)вода\ \]
\[нагревается,\ на\ промежутке\ \]
\[\lbrack 40;60\rbrack\ вода\ кипит,\ вода\ \]
\[остывает\ на\ промежутке\ (60;150\rbrack.\]
\[\boxed{\text{27.\ }\text{ОК\ ГДЗ\ -\ домашка\ на\ 5}}\]
\[\textbf{а)}\ 2,3(4) > 2,(34)\]
\[\textbf{б)}\ 1,05 > 1,0(05)\]
\[\textbf{в)} - 1,34 > - 1,(34)\]
\[\textbf{г)}\ 0,61 < 0,61(1)\]