Xiaoya scored 86 points, 62 points, and 74 points in the previous three tests. What is the minimum score she needs to score on the fourth test if she wants to get an average of 75 out of four times?
小亚前三次测试的成绩分别为86分、62分、74分．如果她想四次平均成绩达到75分，那么她第四次测试的成绩至少要多少分才行？
<gadget id="calculator">75 * 4</gadget>
<output>300</output>

<gadget id="calculator">86 + 62 + 74</gadget>
<output>222</output>

<gadget id="calculator">300 - 222</gadget>
<output>78</output>

<result>78</result>