My wife’s grandmother is a fearsome character. She’s in her nineties but still has all her wits about her. In fact, she’s got more than her fair share of wits. Whenever we visit her, she hits me with a barrage of questions and puzzles collected from the last several decades of TV quiz shows and newspaper games pages. My worth as a grandson-in-law is directly proportional to how many answers I get right.
One of her favourite modes of attack is the “30 Second Challenge” from the Daily Mail. It looks like this:
You start with the number on the left, then follow the instructions reading right until you get to the answer at the end. It’s one of Grandma’s favourites because it’s very hard to do in your head when she’s just reading it out!
I decided it would be a fun Sunday morning mental excursion to make a random 30 second challenge generator.
C: $K_A m; \\ K_B d.$
A: $\neg K_A d; \\ m \vDash \neg K_B m.$
B: $d \not\vDash K_B m; \\ (K_A(\neg K_B m)) \vDash K_B (m,d).$
A: $m \wedge K_B(m,d) \vDash K_A (m,d).$
Albert, Bernard and Cheryl have had a busy week. They’re the stars of #thatlogicproblem, a question from a Singapore maths test that was posted to Facebook by a TV presenter and quickly sent the internet deduction-crazy.
First of all: no, it’s not meant to be answered by an average Singaporean student. It’s a hard question from a schools Olympiad test.
Sam’s dad is in a mathematical conundrum – so she’s asked Katie, one of our editors, if maths can save the day.
Dear The Aperiodical,
My dad is going away on a golfing holiday with seven of his friends and, since I know a little bit about mathematics, he’s asked me to help him work out the best way to arrange the teams for the week. I’ve tried to work out a solution, but can’t seem to find one that fits.
They’ll be playing 5 games during the week, on 5 different days, and they’d like to split the group of 8 people into two teams of four each day. The problem is, they’d each like to play with each of their friends roughly the same amount – so each golfer should be on the same team as each other golfer at least twice, but no more than three times.
Can you help me figure it out?
Sam Coates, Manchester
A while ago I collected a few of the mathsy games I play on my phone to while away my commute. I’ve found a few new ones since then, so I thought I’d do a new post to tell you about them.
Aperiodipal James Grime has put a new video on his YouTube channel. He’s got a problem to do with building houses:
But James posts fantastic videos about maths puzzles all the time; what’s so notable about this one?
I was involved, that’s what! The puzzle can be done on pen and paper but it involves a lot of drawing and calculating, so James asked if anyone could make a computery version. I spent my day off work last week making just such a thing: the computerised Building Houses Problem.
Puzzlebomb is a monthly puzzle compendium. Issue 26 of Puzzlebomb, for February 2014, can be found here:
Puzzlebomb – Issue 26 – February 2014
The solutions to Issue 26 can be found here:
Puzzlebomb – Issue 26 – February 2014 – Solutions
Previous issues of Puzzlebomb, and their solutions, can be found here.