There is a pool full of water, and there is spring water at the bottom of the pool that can always flow out evenly. It is known that 24 A-type water pumps can drain the pool water in 6 days, and if 21 A-type water pumps can drain the pool water in 8 days, set each pump The amount of water pumped per unit time is the same. To make this pool of water never dry, only how many A-type water pumps can be used to pump water at most.
有一满池水，池底有泉水总能均匀地向外涌流，已知用24部A型抽水机6天可抽干池水，若用21部A型抽水机8天也可抽干池水，设每部抽水机单位时间的抽水量相同，要使这一池水永抽不干，则至多只能用多少部A型抽水机抽水．
<gadget id="calculator">21 * 8</gadget>
<output>168</output>

<gadget id="calculator">24 * 6</gadget>
<output>144</output>

<gadget id="calculator">168 - 144</gadget>
<output>24</output>

<gadget id="calculator">8 - 6</gadget>
<output>2</output>

<gadget id="calculator">24 / 2</gadget>
<output>12</output>

<result>12</result>