Both tubes A and B are opened at the same time, and the pool can be filled in 10 minutes. Now open pipe A first, then open pipe B after 9 minutes, and the pool will be filled in 4 minutes. It is known that pipe A injects 0.28 cubic meters more water per minute than pipe B, so what is the volume of the pool in cubic meters?
甲、乙两管同时打开，10分钟就能注满水池．现在先打开甲管，9分钟后再打开乙管，再过4分钟就注满了水池．已知甲管比乙管每分钟多注入0.28立方米的水，那么这个水池的容积是多少立方米．
<gadget id="calculator">1 / 10</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">(1/10) * 4</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 - (2/5)</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">(3/5) / 9</gadget>
<output>1/15 = around 0.066667</output>

<gadget id="calculator">(1/10) - (1/15)</gadget>
<output>1/30 = around 0.033333</output>

<gadget id="calculator">(1/15) - (1/30)</gadget>
<output>1/30 = around 0.033333</output>

<gadget id="calculator">0.28 / (1/30)</gadget>
<output>8.4</output>

<result>8.4</result>