Cars A and B are traveling towards each other from places A and B at the same time. After 4 hours, car A has just reached the midpoint between A and B. Car B has traveled 60% of the entire journey and has traveled 40km more than A. What is the speed of car B?
甲、乙两车分别从A、B两地同时相向而行，4小时后，甲车正好走到A、B的中点，乙车走了全程的60%，且比甲多走40km，求乙车速度是多少？
<gadget id="calculator">60 / 100</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">(3/5) - (1/2)</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">40 / (1/10)</gadget>
<output>400</output>

<gadget id="calculator">(3/5) / 4</gadget>
<output>3/20 = around 0.15</output>

<gadget id="calculator">400 * (3/20)</gadget>
<output>60</output>

<result>60</result>