Mr. Liu went to the bookstore to buy books. Because of the large quantity, the store owner offered a 20% discount. Therefore, Mr. Liu can buy 5 more books than before with 120 yuan. What is the original price of this book?
刘老师去书店买书，由于购买的数量大，店主按八折优惠，因此刘老师用120元可买到的书比原来多5本，那么这本书的原价是多少？
<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

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

<gadget id="calculator">(1/5) / 5 / (4/5)</gadget>
<output>1/20 = around 0.05</output>

<gadget id="calculator">120 * (1/20)</gadget>
<output>6</output>

<result>6</result>