There are 20 people who have contracted a bus. When it was time to leave, it was found that there were 4 more people, so each person paid 3 yuan less than the scheduled price. How much did it cost to contract this bus?
有20人承包了一辆客车，到了出发的时候，发现多来了4人，因此每人比预定的价钱少出了3元，那么承包这辆客车花了多少钱？
<gadget id="calculator">3 * 20</gadget>
<output>60</output>

<gadget id="calculator">3 * 4</gadget>
<output>12</output>

<gadget id="calculator">60 + 12</gadget>
<output>72</output>

<gadget id="calculator">4 - 20</gadget>
<output>-16</output>

<gadget id="calculator">20 + (-16)</gadget>
<output>4</output>

<gadget id="calculator">72 / 4</gadget>
<output>18</output>

<gadget id="calculator">18 * 20</gadget>
<output>360</output>

<result>360</result>