Xiao Ming and Xiao Hong start from the same place at the same time and run in the same direction along a 400-meter circular track. Xiao Ming runs at 90 meters per minute, and Xiao Hong runs at 110 meters per minute. How many minutes does it take for Xiao Ming and Xiao Hong to meet for the first time?
小明和小红两人同时从同一地点出发，沿着400米的环形跑道同方向跑步，小明每分钟90米，小红每分钟110米，经过多少分钟小明和小红第一次相遇？
<gadget id="calculator">110 - 90</gadget>
<output>20</output>

<gadget id="calculator">400 / 20</gadget>
<output>20</output>

<result>20</result>