The school buys desks with a unit price of 140 yuan, and it costs 480 yuan more to buy 30 desks. If you use this money to buy chairs, you can buy 40 chairs. How much is the unit price of each chair?
学校购买每张单价是140元的课桌，买了30张还多480元．如果用这笔钱买椅子，可以买40把．每把椅子的单价是多少元？
<gadget id="calculator">140 * 30</gadget>
<output>4_200</output>

<gadget id="calculator">4_200 + 480</gadget>
<output>4_680</output>

<gadget id="calculator">4_680 / 40</gadget>
<output>117</output>

<result>117</result>