The store decides to sell a product at 80% of the price, so that the profit will only be 40% of the original. It is known that the purchase price of this product is 5 yuan each, and the original plan can make a profit of 800 yuan. how many.
商店决定将某种商品按定价的80%卖出，这样所得利润就只有原来的40%，已知这种商品的进价是每个5元，原计划可获利润800元，这种商品共有多少个．
<gadget id="calculator">800 / 2.5</gadget>
<output>320</output>

<result>320</result>