Are You Smarter Than an 8th Grader?

NYTimes columnist Nicholas Kristof's recent article "Are You Smarter Than an 8th Grader?" tells an interesting story on numeracy taught in our schools. He asks the following questions:

1) What is the sum of the three consecutive whole numbers with 2n as the middle number?     A. 6n+3  B. 6n  C. 6n-1  D. 6n-3

"More than three-quarters of South Korean kids answered correctly (it is B). Only 37 percent of American kids were correct, lagging their peers from Iran, Indonesia and Ghana.”

2) How many degrees does a minute hand of a clock turn through from 6:20 a.m. to 8 a.m. on the same day?

A. 680 degrees   B. 600 degrees   C. 540 degrees   D. 420 degrees

"Only 22 percent of American eighth-graders correctly answered B, below Palestinians, Turks and Armenians."

Kristof finishes his article with a logic puzzle. Be careful, this one may hurt your brain.

You’re in a dungeon with two doors. One leads to escape, the other to execution. There are only two other people in the room, one of whom always tells the truth, while the other always lies. You don’t know which is which, but they know that the other always lies or tells the truth. You can ask one of them one question, but, of course, you don’t know whether you’ll be speaking to the truth-teller or the liar. So what single question can you ask one of them that will enable you to figure out which door is which and make your escape?

Answer: "You ask either of them: 'If I asked the other person which door is the one to escape, which would he point to?' Then you take the other door."