A certain station starts queuing a few minutes before ticket inspection, and the number of passengers coming every minute is the same. It takes 30 minutes to open 5 ticket gates at the same time, and 20 minutes to open 6 ticket gates at the same time from the start of ticket checking to the disappearance of the queue waiting for ticket checking. How many wickets would need to be open to make the line disappear for 10 minutes?
某车站在检票前若干分钟就开始排队，每分钟来的旅客人数一样多．从开始检票到等候检票的队伍消失，同时开5个检票口需30分钟，同时开6个检票口需20分钟．如果要使队伍10分钟消失，需要打开多少个检票口？
<gadget id="calculator">5 * 30</gadget>
<output>150</output>

<gadget id="calculator">6 * 20</gadget>
<output>120</output>

<gadget id="calculator">150 - 120</gadget>
<output>30</output>

<gadget id="calculator">30 - 20</gadget>
<output>10</output>

<gadget id="calculator">30 / 10</gadget>
<output>3</output>

<gadget id="calculator">5 - 3</gadget>
<output>2</output>

<gadget id="calculator">2 * 30</gadget>
<output>60</output>

<gadget id="calculator">10 * 3</gadget>
<output>30</output>

<gadget id="calculator">60 + 30</gadget>
<output>90</output>

<gadget id="calculator">90 / 10</gadget>
<output>9</output>

<result>9</result>