Two brothers ride bicycles from A to B at the same time. The younger brother travels 4 kilometers per hour for the first half of the journey, and 6 kilometers per hour for the second half of the journey. My brother drives according to time, 4 kilometers per hour in the first (1/3) time, 5 kilometers per hour in the middle (1/3) time, and 6,000 kilometers per hour in the last (1/3) time m, the elder brother arrived 20 minutes earlier than the younger brother. Question: How many miles is the distance between A and B?
兄弟两人骑自行车同时从甲地到乙地，弟弟在前一半路程每小时行4千米，后一半路程每小时行6千米．哥哥按时间分段行驶，前(1/3)的时间每小时行4千米，中间(1/3)的时间每小时行5千米，最后(1/3)的时间每小时行6千米，结果哥哥比弟弟早到20分钟．问：甲、乙两地相距多少千米？
<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">3 + 2</gadget>
<output>5</output>

<gadget id="calculator">3 / 5</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">(1/3) * (3/5) * 4</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">(1/3) * (2/5) * 6</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">(4/5) + (4/5)</gadget>
<output>8/5 = around 1.6</output>

<gadget id="calculator">(1/3) * 4</gadget>
<output>4/3 = around 1.333333</output>

<gadget id="calculator">(1/3) * 5</gadget>
<output>5/3 = around 1.666667</output>

<gadget id="calculator">(1/3) * 6</gadget>
<output>2</output>

<gadget id="calculator">(3/5) * 4</gadget>
<output>12/5 = around 2.4</output>

<gadget id="calculator">(2/5) * 6</gadget>
<output>12/5 = around 2.4</output>

<gadget id="calculator">2 - (12/5) - (12/5)</gadget>
<output>-14/5 = around -2.8</output>

<gadget id="calculator">(4/3) + (5/3) + (-14/5)</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">(8/5) / (1/5)</gadget>
<output>8</output>

<gadget id="calculator">8 * 5</gadget>
<output>40</output>

<result>40</result>