Every morning Xiaobing leaves home to go to school on time, and Uncle Zhang also goes out for a walk regularly, and they meet each other at the same place and at the same time every day; one day, Xiaobing leaves home early and meets Uncle Zhang 7 minutes earlier than usual. Mi, Uncle Zhang walks 40 meters per minute. How many minutes earlier did the soldier go out this day?
每天早晨小兵准时离家上学，张大爷也定时出门散步，并且每天两人都在同一地点同一时刻相遇；某天小兵提前出门，结果比平时早7分钟与张大爷相遇，若小兵每分钟走70米，张大爷每分钟走40米，这一天小兵比平时早几分钟出门？
<gadget id="calculator">70 / 40</gadget>
<output>7/4 = around 1.75</output>

<gadget id="calculator">1 / (7/4)</gadget>
<output>4/7 = around 0.571429</output>

<gadget id="calculator">7 * (4/7)</gadget>
<output>4</output>

<gadget id="calculator">4 + 7</gadget>
<output>11</output>

<result>11</result>