During the New Year’s Day, a store bought 500 greeting cards at a price of 0.5 yuan each, and then sold 370 cards at a price of 1.5 yuan each, and sold the rest with a 20% discount. Profitability of batches of greeting cards.
元旦期间，某商店以每张0.5元的价格购进500张贺卡，再以每张1.5元的价格卖出了370张，剩下的打八折出售，全部售完，求这家商店卖这批贺卡的盈利率．
<gadget id="calculator">1.5 * 370</gadget>
<output>555</output>

<gadget id="calculator">80 / 100</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">500 - 370</gadget>
<output>130</output>

<gadget id="calculator">0.5 * (4/5) * 130</gadget>
<output>52</output>

<gadget id="calculator">0.5 * 500</gadget>
<output>250</output>

<gadget id="calculator">52 - 250</gadget>
<output>-198</output>

<gadget id="calculator">555 + (-198)</gadget>
<output>357</output>

<gadget id="calculator">357 / 250</gadget>
<output>357/250 = around 1.428</output>

<result>357/250 = around 1.428</result>