Logic Puzzles Dell Magazine

LOGII If you've never solved a logic puzzle before, this introduction wiil show you how. We'll take you step by step through two

in the intersections of'Abner" and "Gunter," and "Abner" and "King cobra."

simple logic puzzles, and give you some solving tips along the

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way.

logic p,.,zrl" is a test ofyour abihLy to think clearly You don'r need dictionaries or other reference books to solve a logic just a pencil and plenty of common sense' puzzle, Usualiy, a logic puzzle asks you to match up sets of things' For exanple. you might be told lhat four men each own an exotic pet, and to solve the puzzle you'd -match up each man's first nime \ /ith his last name and his kind of pet. You figrrr:e *Ihe out how to mat h them up by studying a list ofclues, like to Duane." belong llama doesnt In order to make solving fa-ster and easier, experienced logic puzzlers use a solving grid to record the information they've deduced. They've found that seeing the inforrnation in black and white, neatly organized, helps them make furiher deductions. lhere are two kinds of solving grids you'll find most often: the "crosshatch" grid and the "fiIl-in" grid. Sometimes you can't tell.which kind will work best until you've spent a lot of time trying to solve the puzzle with the wrong ki^d. In Dell logia Puzzles, we figure out which kind of grid is the most useful for each puzzle, and we print it on the same page. Sometimes we'll even give you both kinds if we think it will help. Let's look at a typical puzzle that works best with a crosshatch grid.

i

PET OWNERS

Each of four men owns a different species of exotic pet. .F rom the following clues, can you frgure out each man's full name and what kind of pet he owns? 1, Mr..Engels (whose pet is named Sparky), Abner, and Mr. Foster all belong to a club for owners of unusual pets. 2. The iguana i6n't owrred by either Chuck or Duane. 3. Neither the jackal nor the king cobra is owned by Mr. Foster. 4. The llama doesn't belong to Duane (whose pet is named Waggles).

5: Abner, who doesn't own the king cobra, isn't Mr. Grint€r. 6. Bruce and Mr. Foster are neighbors. 7. Mr. Halera is afraid of iguanas. And heret the crosshatch grid:

I4t's look first at clue 1. From it we can see that !{bner isrit Mr. Engels or Mr. Foster. We record this information in the

solving grid by pr-rtting an X rmeaning -no", in the square at the intersection of "Abner" and "Engels," anil another X at the intersection of "Abner- and 'Foster." Now let's look at clue 5. From it we learn that Abner doesn't ovfir the king cobra, and that Alner isn't Mr. Gunt€r..Put Xs

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DELL LOGIC PUZZLES February 1995

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werc care)ess. you mighl witho'.rt *rinking put an X into !the intersection of 'Gunted and fiing cobra' Does Mr. Gunter{ own the king cobra? Well, maybe he dnes and maybe he doeso't. i bul clue 5 really doesnt say anl'thing about it. Read each cluef, carefirlly and think about what it's really saying; if you jump to I a wrong conclusion now, you'lJ be confilsed later on. 1

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Now we can se€ at a glance lhat Abner isn't Mr. Engels, Mr. I Foster, or Mr. Cunl,er. We can make a deduction: Abner must t be Mr. Halew. We'tl pr-rt a large dot (meaning :yes') in the I intersection of 'Abner" and -Halera." And that meals we can -l put )Cs in rhe intarsecl ions of fialeqa and "Bruce." 'Chuck," ll also -'Duare." \^/henever you add a dot to lhe grid, be sure ln', ar|d add any Ks you can: Lhej,4l ofien lead to more dedtrctions

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|$fam lnls l( -

ffi X

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x

Bruce

F:*FF+]T Chuck

X

Duane

X

That was a fairlv simple deduction, but in order to solve this puzzle you'll need to make some deductions that are a little i.i"ti... Go through the rest of the clues,and. pu-t Xs into ihe grid wherever you can. You'll end up with this:

Sometimes, with a very easy puzzle. just putting the informaQori lhts lall out oul- to you This solurion fall the solution srid is enough enoush to make ttre in the grid

putzle'i a bit harder, though, and at first glance th9r9 dTsn't seem to be enoueh inforrn;tion to mal