Aunt Li goes to the grain and oil store to buy rice. If she buys 20kg of rice, she will have 7.5 yuan left. If she buys 25kg of the same rice. So there is still a difference of 7.5 yuan. How much did Aunt Li bring?
李阿姨到粮油店买米，如果买20kg大米，那么所带的钱还剩7.5元，如果买同样的大米25kg．那么还差7.5元，李阿姨带了多少元？
<gadget id="calculator">7.5 + 7.5</gadget>
<output>15</output>

<gadget id="calculator">25 - 20</gadget>
<output>5</output>

<gadget id="calculator">15 / 5</gadget>
<output>3</output>

<gadget id="calculator">3 * 20</gadget>
<output>60</output>

<gadget id="calculator">60 + 7.5</gadget>
<output>67.5</output>

<result>67.5</result>