On Sunday, Xiao Ming and his father went for an outing by bicycle. They rode 20% of the whole journey in the first hour, and rode 4 kilometers less in the second hour than in the first hour. At this time, there is still 65% of the whole journey away from the destination. Find the whole journey.
周日，小明和爸爸骑自行车去郊游，第一小时骑了全程的20%，第二小时比第一小时少骑了4千米．此时距目的地还有全程的65%，求全程．
<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">65 / 100</gadget>
<output>13/20 = around 0.65</output>

<gadget id="calculator">(13/20) - 1</gadget>
<output>-7/20 = around -0.35</output>

<gadget id="calculator">(1/5) + (1/5) + (-7/20)</gadget>
<output>1/20 = around 0.05</output>

<gadget id="calculator">4 / (1/20)</gadget>
<output>80</output>

<result>80</result>