A Four-Letter Word For Capital City
Correction Nov. 14, 2011
Some numbers were left out of the number series for next week's challenge, both on the air and in a previous version of the Web text. The correct sequence should be 2, 4, 6, 9, 11, 15, 20, 40, 51, 55, 60 and 90.
On-Air Challenge: Every answer is the name of a world capital. You'll be given a four-letter word. The first two letters are the first two letters of the city's name, and the last two are the last two letters of the country's name. For example, if you were given "loin," the answer would be London, Great Britain.
Last Week's Challenge from the Grabarchuk family: Take 15 coins. Arrange them in an equilateral triangle with one coin at the top, two coins touching below, three coins below that, then four, then five. Remove the three coins at the corners so you're left with 12 coins. Using the centers of the 12 coins as points, how many equilateral triangles can you find by joining points with lines?
Answer: 25 equilateral triangles
Winner: Chris Anderson from Portland, Ore.
Next Week's Challenge from listener Henry Hook of Brooklyn, N.Y.: What number comes next in the following series: 2, 4, 6, 9, 11, 15, 20, 40, 51, 55, 60 and 90?
If you know the answer to next week's challenge, submit it here. Listeners who submit correct answers win a chance to play the on-air puzzle. Important: Include a phone number where we can reach you Thursday at 3 p.m. Eastern.
More Sunday Puzzle

Sunday Puzzle
Initially Famous 2: Electric Boogaloo
Given clues for some famous people, the initials of the clues are also the initials of the answers.

Sunday Puzzle
You Two, Move To The Back Of The Line
Every answer is a six-letter word. Move the first two letters to the end and you get another word.
Sunday Puzzle
Brave Sir Robin Ran Away, But The Puzzle Is Still OK
Name something in a given category beginning with each of the letters of the word "robin."


Comments
Discussions for this story are now closed. Please see the Community FAQ for more information.