The selling price of a certain schoolbag after a 20% discount is 120 yuan. If it is sold at a 10% discount, how much does this schoolbag cost?
某款书包打八折后售价是120元，如果打九折出售，这款书包需要多少元．
<gadget id="calculator">80 / 100</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">120 / (4/5)</gadget>
<output>150</output>

<gadget id="calculator">90 / 100</gadget>
<output>9/10 = around 0.9</output>

<gadget id="calculator">150 * (9/10)</gadget>
<output>135</output>

<result>135</result>