A store buys a batch of photo albums at 10.9 yuan each and sells them at 14 yuan each. When (4/5) of this batch of photo albums are sold, not only the full cost is recovered, but also a profit of 150 yuan is made. How many copies are there in this batch of photo albums?
某商店以每本10.9元够进一批相册，以每本14元卖出，当卖出这批相册的(4/5)时，不仅收回了全部成本，而且还获利150元．这批相册一共有多少本？
<gadget id="calculator">4 / 5</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">14 * (4/5)</gadget>
<output>56/5 = around 11.2</output>

<gadget id="calculator">(56/5) - 10.9</gadget>
<output>0.3</output>

<gadget id="calculator">150 / 0.3</gadget>
<output>500</output>

<result>500</result>