One day, there were 945 tourists waiting at the entrance of the China Pavilion at the Shanghai World Expo. At this time, there are still several people coming to the entrance to enter the museum every minute. In this way, if 4 ticket gates are opened, all tourists can enter the museum within 15 minutes; if 8 ticket gates are opened, all tourists can enter the museum within 7 minutes. Now it is required that all tourists enter the museum within 5 minutes, how many ticket gates need to be opened.
某天上海世博会中国馆入口处已有945名游客等候检票进馆．此时，每分钟还有若干人前来入口处准备进馆．这样，如果打开4个检票口，15分钟游客可以全部进馆；如果打开8个检票口，7分钟游客可以全部进馆．现在要求在5分钟内所有游客全部进馆，需要打开多少个检票口．
<gadget id="calculator">15 * 4</gadget>
<output>60</output>

<gadget id="calculator">7 * 8</gadget>
<output>56</output>

<gadget id="calculator">60 - 56</gadget>
<output>4</output>

<gadget id="calculator">15 - 7</gadget>
<output>8</output>

<gadget id="calculator">4 / 8</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">(1/2) * 15</gadget>
<output>15/2 = around 7.5</output>

<gadget id="calculator">60 - (15/2)</gadget>
<output>105/2 = around 52.5</output>

<gadget id="calculator">945 / (105/2)</gadget>
<output>18</output>

<gadget id="calculator">(1/2) * 18 * 5</gadget>
<output>45</output>

<gadget id="calculator">945 + 45</gadget>
<output>990</output>

<gadget id="calculator">18 * 5</gadget>
<output>90</output>

<gadget id="calculator">990 / 90</gadget>
<output>11</output>

<result>11</result>