Car A drives from point A to point B at 40 kilometers per hour. After driving for 5 hours, car B also drives from point A to point B at a speed of 90 kilometers per hour. At the midpoint between places A and B, car B catches up with car A. How many kilometers are there between places A and B?
甲车从A地开往B地，每小时行40千米，开出5小时后，乙车以每小时90千米的速度也从A地开往B地．在A、B两地的中点处乙车追上甲车，A、B两地相距多少千米？
<gadget id="calculator">90 - 40</gadget>
<output>50</output>

<gadget id="calculator">5 / 50</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">40 * (1/10) * 90 * 2</gadget>
<output>720</output>

<result>720</result>