The Quarter-Sized Car Fix

Alright, a true automotive puzzler:

A guy is working under his car. After a while, he rolls out, spots something on the ground—about the size of a quarter—picks it up, and looks… disappointed.

He goes inside, comes back with a vacuum cleaner, hooks the hose up under the hood, turns it on, crawls back under the car with the little object…

A minute later, he comes out smiling, shuts off the vacuum, and the job is done.

What did he do and why did he need the vacuum cleaner?

Answer the Puzzler »

Remember last week's puzzler?

Magic Hat of Consecutive Numbers

Alright, this one may be the puzzler of the millennium, no pressure.

We’ve got a magic hat and two contestants: you and Vinnie.

Each of you pulls out a number. Here’s the twist: Your numbers are always one apart.

So if you pick 3, Vinnie has either 2 or 4.

I ask you: “Do you know Vinnie’s number?”

You say, “No.”

I ask Vinnie: “Do you know Tommy’s number?”

He might say yes… or no.

We keep going back and forth, each time asking, “Do you know the other guy’s number?”

Eventually—after enough “no’s”— one of you suddenly knows the other’s number for sure.

Why does repeated questioning eventually guarantee that one of them figures it out?