A repeater was priced at 750 yuan. After a week, it was discounted by 10% and still not sold. Later, it was sold after a 20% discount. What is the final selling price of this repeater?
一种复读机的标价是750元，一周后打九折仍没有卖出，后来又打了八折才卖出，这台复读机的最终卖价是多少元．
<gadget id="calculator">90 / 100</gadget>
<output>9/10 = around 0.9</output>

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

<gadget id="calculator">750 * (9/10) * (4/5)</gadget>
<output>540</output>

<result>540</result>