There are already people queuing up at the ticket gate of a railway station before the start of ticket checking. After the start of ticket checking, there are an average of 10 people queuing up to wait for ticket checking every minute. A ticket gate can allow 25 people to check tickets into the station on average every minute. If only one ticket gate is opened, no one will be in line 8 minutes after the ticket check starts; if two ticket gates are opened, no one will be in line for a while after the ticket check starts.
某火车站的检票口在检票开始前已经有人在排队，检票开始后平均每分钟有10人来排队等候检票．一个检票口每分钟平均能让25人检票进站．如果只开一个检票口，那么检票开始8分钟后就可以无人排队；如果开两个检票口，那么开始检票多少分钟后就暂时无人排队了．
<gadget id="calculator">25 * 8</gadget>
<output>200</output>

<gadget id="calculator">10 * 8</gadget>
<output>80</output>

<gadget id="calculator">200 - 80</gadget>
<output>120</output>

<gadget id="calculator">25 * 2</gadget>
<output>50</output>

<gadget id="calculator">50 - 10</gadget>
<output>40</output>

<gadget id="calculator">120 / 40</gadget>
<output>3</output>

<result>3</result>