It is known that two kinds of fruits with a unit price of 2 yuan and 2.5 yuan bought a total of 5 catties, and the shared cost is 11 yuan, so how many catties of fruits with a unit price of 2 yuan were bought.
已知单价为2元和2.5元的两种水果一共买了5斤，共用去11元，则单价为2元的水果买了多少斤．
<gadget id="calculator">2.5 * 5</gadget>
<output>12.5</output>

<gadget id="calculator">12.5 - 11</gadget>
<output>1.5</output>

<gadget id="calculator">2.5 - 2</gadget>
<output>0.5</output>

<gadget id="calculator">1.5 / 0.5</gadget>
<output>3</output>

<result>3</result>