Question 1071964
.
<pre>
The linear interpolation between 11 hours and 23 hours gives the formula for the candle height


h(t) = {{{26.8 - ((26.6-24.4)/(23-11))*(t-11)}}} =  {{{26.8 - (2.4/12)*(t-11)}}} = {{{26.8 - 0.2*(t-11)}}},


where t is the time of burning in hours (between 11 and 20).


Then h(20) = {{{26.8 - 0.2*(20-11)}}} = 25 cm.
</pre>

<U>Answer</U>. 25 centimeters.