Alone in Your Dim, Unheated Room You Light One Candle ${ } ^ { \circ } F$

Alone in your dim, unheated room you light one candle rather than curse the darkness.Disgusted by the mess, you walk directly away from the candle.The temperature (in ${ } ^ { \circ } F$ )and illumination (in % of one candle power)decrease as your distance (in feet)from the candle increases.The table below shows this information.
$\begin{array}{ccc}\text { distance(feet) } & \text { Temp. }\left({ }^{0} \mathrm{~F}\right) & \text { illumination } \\0 & 56 & 100 \\1 & 55.5 & 85 \\2 & 54.5 & 75 \\3 & 53 & 67 \\4 & 51 & 60 \\5 & 48 & 56 \\6 & 44 . 5& 53\end{array}$ What is the average rate at which the temperature is changing (in degrees per foot)when the illumination drops from 75% to 56%? Round to 2 decimal places.