The general affairs of the school brought some money to buy desks and chairs for the students. If you buy 28 sets, there will be 1260 yuan left, and if you buy 42 sets, there will be 140 yuan left. How much did the general affairs bring?
学校总务带了一些钱要给同学们买桌椅，如果买28套，还剩1260元，如果买42套，还剩140元，总务共带了多少钱？
<gadget id="calculator">1_260 - 140</gadget>
<output>1_120</output>

<gadget id="calculator">42 - 28</gadget>
<output>14</output>

<gadget id="calculator">1_120 / 14</gadget>
<output>80</output>

<gadget id="calculator">80 * 28</gadget>
<output>2_240</output>

<gadget id="calculator">2_240 + 1_260</gadget>
<output>3_500</output>

<result>3_500</result>