It costs 6.90 yuan to buy 3 catties of apples and 2 catties of oranges; it costs 22.80 yuan to buy 8 catties of apples and 9 catties of oranges, so how much does it cost to buy 1 catty of apples and oranges?
购买3斤苹果，2斤桔子需6.90元；购8斤苹果，9斤桔子需22.80元，那么苹果、桔子各买1斤需多少元．
<gadget id="calculator">6.9 + 22.8</gadget>
<output>29.7</output>

<gadget id="calculator">3 + 8</gadget>
<output>11</output>

<gadget id="calculator">29.7 / 11</gadget>
<output>2.7</output>

<result>2.7</result>