It takes 20 minutes for the oil to heat up to 300 degrees.  It then takes 40% longer for the oil to heat up to the desired temperature of 400 degrees.  After warming the oil it takes 5 minutes less time to cook than it took to warm up the oil.  How much time passes from starting the oil to having cooked chicken?
It takes 20*.4=8 more minutes to go from 300 to 400 degrees than from room temperature to 300.
So it takes 20+8=
<gadget id="calculator">20+8</gadget>
<output>28</output>
28 minutes to warm up.
So the total warming time was 28+20=
<gadget id="calculator">28+20</gadget>
<output>48</output>
48 minutes.
So it took 48-5=
<gadget id="calculator">48-5</gadget>
<output>43</output>
43 minutes to cook the chicken.
So it took 48+43=
<gadget id="calculator">48+43</gadget>
<output>91</output>
91 minutes to make the chicken.

<result>91</result>