Originally, I could buy 150 pens, but after the price was reduced to 4.5 yuan each, I bought 160 pens. What was the original price?
原来可以买150支笔，后来降价后每支4.5元，买了160支，原价是多少元一支．
<gadget id="calculator">160 / 150</gadget>
<output>16/15 = around 1.066667</output>

<gadget id="calculator">4.5 * (16/15)</gadget>
<output>4.8</output>

<result>4.8</result>