The price of a desk is 120 yuan, which is equivalent to the price of 3 chairs. The school bought 20 new chairs. How much did you spend on the chairs?
一张课桌的价钱是120元，相当于3把椅子的价钱，学校新添置了20把椅子，买椅子共花去了多少钱？
<gadget id="calculator">120 / 3</gadget>
<output>40</output>

<gadget id="calculator">40 * 20</gadget>
<output>800</output>

<result>800</result>