There are 69 cars in the parking lot, which is 15 less than three times the number of minibuses. How many minibuses are there? (solution by equation)
停车场里有小汽车69辆，比中巴车辆数的3倍少15辆，中巴车有多少辆？(用方程解)
<gadget id="calculator">69 + 15</gadget>
<output>84</output>

<gadget id="calculator">84 / 3</gadget>
<output>28</output>

<result>28</result>