A cistern is equipped with an inlet pipe and several outlet pipes, and the inlet pipe injects 2 cubic meters of water per minute. If the water inlet pipe and the three outlet pipes are opened at the same time, the whole pool can be emptied in 1 hour and 30 minutes. If the water inlet pipe and 5 outlet pipes are opened at the same time, the whole pool can be emptied in 50 minutes. Now find the water inlet pipe and 8 outlet pipes at the same time, how long will it take to empty the whole pool of water?
一个蓄水池，装有一根进水管和若干根出水管，进水管每分钟注入水2立方米．如果同时打开进水管和3根出水管，1小时30分钟可把全池水放空．如果同时打开进水管和5根出水管，则50分钟就可把全池水放空．现在同时找开进水管和8根出水管，要多少时间才能把全池水放空．
<gadget id="calculator">2 * 90</gadget>
<output>180</output>

<gadget id="calculator">2 * 50</gadget>
<output>100</output>

<gadget id="calculator">180 - 100</gadget>
<output>80</output>

<gadget id="calculator">3 * 90</gadget>
<output>270</output>

<gadget id="calculator">5 * 50</gadget>
<output>250</output>

<gadget id="calculator">270 - 250</gadget>
<output>20</output>

<gadget id="calculator">80 / 20</gadget>
<output>4</output>

<gadget id="calculator">4 * 3 * 90</gadget>
<output>1_080</output>

<gadget id="calculator">1_080 - 180</gadget>
<output>900</output>

<gadget id="calculator">4 * 8</gadget>
<output>32</output>

<gadget id="calculator">32 - 2</gadget>
<output>30</output>

<gadget id="calculator">900 / 30</gadget>
<output>30</output>

<result>30</result>