A person plans to ride a bicycle from point A to point B at a speed of 12 kilometers per hour, so that he can reach point B within the specified time. Going forward at a speed of 15 kilometers, and finally arrives at point B 4 minutes earlier than the specified time, find the distance between points A and B.
某人计划骑车以每小时12千米的速度由A地到B地，这样便可在规定的时间到达B地，但他因事将原计划的时间推迟了20分，便只好以每小时15千米的速度前进，结果比规定时间早4分钟到达B地，求A、B两地间的距离．
<gadget id="calculator">20 / 60</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">12 * (1/3)</gadget>
<output>4</output>

<gadget id="calculator">4 / 60</gadget>
<output>1/15 = around 0.066667</output>

<gadget id="calculator">15 * (1/15)</gadget>
<output>1</output>

<gadget id="calculator">4 + 1</gadget>
<output>5</output>

<gadget id="calculator">15 - 12</gadget>
<output>3</output>

<gadget id="calculator">5 / 3</gadget>
<output>5/3 = around 1.666667</output>

<gadget id="calculator">12 * (5/3)</gadget>
<output>20</output>

<result>20</result>