A shopping mall sells a jacket at 50% of the purchase price and then sells it at a 20% discount, making a profit of 30 yuan. What is the purchase price of this jacket?
某商场将一件上衣按进价的50%加价后再按八折售出，获利30元，这件上衣进价多少元．
<gadget id="calculator">80 / 100</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">50 / 100</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">(1/2) * (4/5)</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">(2/5) - 1</gadget>
<output>-3/5 = around -0.6</output>

<gadget id="calculator">(4/5) + (-3/5)</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">30 / (1/5)</gadget>
<output>150</output>

<result>150</result>