Each desk is 60 yuan, and each chair is 15 yuan cheaper than each table. How much does it cost the school to buy 30 sets of desks and chairs?
每张课桌60元，每把椅子比每张桌子便宜15元，学校买30套桌椅，要花多少钱？
<gadget id="calculator">60 - 15</gadget>
<output>45</output>

<gadget id="calculator">45 + 60</gadget>
<output>105</output>

<gadget id="calculator">105 * 30</gadget>
<output>3_150</output>

<result>3_150</result>