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SAT GUESSING
考试靠猜
Q. What if everyone who took the SAT guessed on every multiple-choice question? How many perfect scores would there be?
Q．如果每个参加美国高考（SAT）的学生都在选择题部分乱猜一气会怎么样？有多少人会获得满分？
——Rob Balder
——罗布•鲍尔德
A. NONE.
A．没人。
The SAT is a standardized test given to American high school students. The scoring is such that under certain circumstances, guessing an answer can be a good strategy. But what if you guessed on everything?
SAT考试是给美国高中学生参加的标准化测试，在一些情况下，乱猜一个答案是一个不错的选择。但如果你所有题目都乱猜呢？
Not all of the SAT is multiple-choice, so let's focus on the multiple-choice questions to keep things simple. We'll assume everyone gets the essay questions and fill-in-the-number sections correct.
SAT考试并非全部都是选择题，为了把问题简单化，我们假定只在选择题部分乱猜答案，并假设所有人在写作题目和填空部分都拿了满分。
In the 2014 version of the SAT, there were 44 multiple-choice questions in the math (quantitative) section, 67 in the critical reading (qualitative) section, and 47 in the newfangled1 writing section. Each question has five options, so a random guess has a 20 percent chance of being right.
在2014年的SAT考试中，数学部分有44道选择题，批判性阅读部分有67道，新式1的写作部分有47道。每道选择题有5个选项，因而乱猜一个答案有20％的几率能够猜对。
The probability of getting all 158 questions right is:
所有158道选择题都猜对的几率为：
If all four million 17-year-olds took the SAT, and they all guessed randomly, it's a virtually certain that there would be no perfect scores on any of the three sections.
如果全部400万17岁的孩子都去参加SAT考试瞎猜答案，那么几乎可以肯定的是，在三个部分中的任何一个部分都不会有满分出现。
How certain is it? Well, if they each used a computer to take the test a million times each day, and continued this every day for five billion years-until the Sun expanded to a red giant and the Earth was charred to a cinder-the chance of any of them ever getting a perfect score on just the math section would be about 0.0001 percent.
有多肯定？假设他们每天用计算机参加100万次考试，并且持续50亿年——直到太阳膨胀成一颗红巨星，将地球烧成渣——在这么多次考试中，仅仅数学部分得到满分的几率只有万分之一。
How unlikely is that? Each year something like 500 Americans are struck by lightning (based on an average of 45 lightning deaths and a 9–10 percent fatality rate). This suggests that the odds of any one American being hit in a given year are about 1 in 700,000.2
这几率有多小？每年有大约500名美国人被闪电击中（平均每年有45人死于雷击，被雷击的死亡率约为9％～10％）。这意味着指定某一年任选一个美国人，他被闪电击中的几率是七十万分之一。2
This means that the odds of acing the SAT by guessing are worse than the odds of every living ex-President and every member of the main cast of Firefly all being independently struck by lightning . . . on the same day.
这意味着如果想通过乱猜获得SAT考试满分，这个几率比所有健在的前总统加上《萤火虫》3的全部主演们都在同一天被闪电击中的几率还小。
To everyone taking the SAT this year, good luck-but it won't be enough.
致今年参加SAT考试的各位，祝你们好运啦——虽然光靠运气是没用的。
1 I took the SAT a long time ago, okay?
1． 很久以前我考过SAT考试，行了吧？
