Xiaohua bought 3 packs of potato chips and 2 boxes of jelly in the supermarket, and spent a total of 12.9 yuan. It is known that each bag of potato chips costs 2.3 yuan more than each box of jelly, how much is each bag of potato chips.
小华在超市买了3包薯片和2盒果冻，一共花了12.9元．已知每包薯片比每盒果冻多花2.3元，每包薯片多少元．
<gadget id="calculator">2.3 * 2</gadget>
<output>4.6</output>

<gadget id="calculator">12.9 + 4.6</gadget>
<output>17.5</output>

<gadget id="calculator">3 + 2</gadget>
<output>5</output>

<gadget id="calculator">17.5 / 5</gadget>
<output>3.5</output>

<result>3.5</result>