20: The middle digit [**]

Aug 28, 20162:51Games & Hobbies

How many three-digit numbers satisfy the property that the middle digit is the average of the first and the last digits? // Spiciness: ** out of ****

Related Episodes

Continue listening to more episodes from Wes Carroll's Puzzler.

Dec 25, 2016 - 3:59

A parking lot has 16 spaces in a row. Twelve cars arrive, each of which requires one parking space, and t...

Nov 6, 2016 - 4:58

What’s the largest 2-digit prime factor of “200 choose 100”? // Spiciness: *** out of ****

Oct 2, 2016 - 2:41

Last week, two of my friends and I went to a restaurant and had a lovely meal. We decided to evenly split...

Sep 4, 2016 - 2:40

A faulty car odometer proceeds from digit 3 to digit 5, always skipping the digit 4, regardless of positi...

Aug 14, 2016 - 2:44

A game is played with tokens according to the following rule. In each round, the player with the most tok...

Jul 31, 2016 - 6:34

Brenda and Sally run in opposite directions on a circular track, starting at diametrically opposite point...

Jul 24, 2016 - 3:35

My perpetually tricky friend told me that while she was walking through town she saw four particularly vi...

Jul 17, 2016 - 4:27

A friend of mine told me that she can walk a mile south, a mile east, a mile north and end up back home....