A barrel of oil weighs 122.5 kilograms. After selling half of the oil, the barrels still weigh 62.5 kilograms. The barrel of oil was sold for 510 yuan. How much is the price of oil per kilogram?
一桶油连桶重122.5千克，卖出油的一半后，连桶还重62.5千克，这桶油共卖了510元．每千克油价是多少元？
<gadget id="calculator">122.5 - 62.5</gadget>
<output>60</output>

<gadget id="calculator">60 * 2</gadget>
<output>120</output>

<gadget id="calculator">510 / 120</gadget>
<output>17/4 = around 4.25</output>

<result>17/4 = around 4.25</result>