A Manufacturer of Personal Computers Tests Competing Brands and Finds $\left[ \begin{array} { l l } 269.76 & 300.24\end{array} \right]$

A manufacturer of personal computers tests competing brands and finds that the amount of energy they require is normally distributed with a mean of 285 kwh and a standard deviation of 9.1 kwh.If the lowest 25 percent and the highest 30 percent are not included in a second round of tests,what are the upper and lower limits for the energy amounts of the remaining computers?

A) $\left[ \begin{array} { l l } 269.76 & 300.24\end{array} \right]$
B) $\left[ \begin{array} { l l } 269.76 & 289.78\end{array} \right]$
C) $[ 280.22$ $\quad$$\quad$$289.78 ]$
D) $\left[ \begin{array} { l l } 280.22 & 300.24\end{array} \right]$