Hot Dog Contest

Logic Level 1

Bill, David, and Joey are the 3 finalists in a hot dog eating contest.

  • Bill did not eat the fewest hot dogs.
  • David did not eat the greatest number of hot dogs.
  • Joey ate more hot dogs than Bill.

Who won the contest by eating the most hot dogs?

Bill David Joey

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11 solutions

Peter Macgregor
May 8, 2017

There is a solution based on just the first and last statements!

The first statement tells us that Bill did not come last.

The third statement tells us that Joey ate more hot dogs than Bill.

And so Joey must be first.

Moderator note:

All possible orders are charted above (using B, D, and J for Bob, David and Joey respectively), listed from least hot dogs eaten to most.

When considering the statement alone, one of the form "<person> ate more than <person>" removes 3 of the possible orders.

When considering the statement alone, one of the form "<person> did not place in <specific place>" removes two of the possible orders.

In this case, the 2 orders removed by the statement "Bill did not eat the fewest number of hot dogs" are both contained within the 3 orders still remaining after applying "Joey ate more hot dogs than Bill" which is why the second clue was not needed.

If the first clue had instead been (for example) "David did not end in 2nd place", only 1 order could have been removed from the 3 remaining, so the second clue would have been necessary.

Good observation. Because Bill did not come last, he must be the winner or the first runner-up. Anyone ate more than him must be the winner.

Christopher Boo - 4 years, 1 month ago

The second and third statements are also sufficient to conclude that Joey ended in the first place, but we need the first statement to find the order of Bill and David.

Pranshu Gaba - 4 years, 1 month ago

This would have been harder if we were asked the order.

Whitney Clark - 4 years, 1 month ago
Mohammad Khaza
May 8, 2017

David did not eat the highest. So, Bill and Joey are in the race.but Joey eats more than Bill. So, Joey is the winner.

It's clear when you phrase it this way. Nice simplification!

Christopher Boo - 4 years, 1 month ago

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thanks.your comment inspired me

Mohammad Khaza - 4 years, 1 month ago

This is the way I did it too. Well done.

Stan Latesty - 4 years, 1 month ago

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thanks for your comment.

Mohammad Khaza - 4 years ago

good explanation

Halima Tahmina - 4 years ago

thanks.your comment inspired me

Mohammad Khaza - 4 years ago
Tapas Mazumdar
May 1, 2017

Let us provide ranks 1 , 2 1,2 and 3 3 and check the possibilities one by one

Bill did not eat the fewest hot dogs.

  • This means that Bill can have a rank : { 1 , 2 } \{1,2\}

David did not eat the most number of hot dogs.

  • So David's rank can be : { 2 , 3 } \{2,3\}

Joey ate more hot dogs than Bill.

  • Thus, Joey's rank numerically is one less than Bill's rank and can be : { 1 1 , 2 1 } = { 0 , 1 } \{1-1,2-1\} = \{0,1\}

But there's no such a rank as a 0 0 rank since we have assumed the ranks to be 1 , 2 1,2 and 3 3 only. Thus we conclude that Joey's rank is 1 1 , Bill's rank is 2 2 and David's rank is 3 3 . So Joey ate the most number of hot dogs and won the contest.

Bon Appétit !

Excellent deduction. By the way, I think we could use some constraint programming language like prolog or minizinc to do this deduction as well

Agnishom Chattopadhyay - 4 years, 1 month ago

It's not as complicated as provided in the solution. The solution can be determined upon inspection, if not intuitively.

Bill did not eat the fewest hot dogs = He's not in 3rd place, he's in 1st or 2nd place David did not eat the most number of hot dogs = He's not in 1st place and can't be the winner Joey ate more hot dogs than Bill = Joey defeats Bill and Joey is the winner

Marcel Noya - 4 years, 1 month ago

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It might seem 'complicated', but if you ask me it is really systematic and makes work on larger problems much more workable.

Peter van der Linden - 4 years, 1 month ago

let

rank 1= fewest number of hotdogs \text {rank 1= fewest number of hotdogs}

rank 2 = more than fewest but less than most number of hotdogs \text{rank 2 = more than fewest but less than most number of hotdogs}

rank 3 = most number of hotdogs \text{rank 3 = most number of hotdogs}

From the first statement: Bill maybe rank 2 2 or 3 3 .

From the second statement: David maybe rank 1 1 or 2 2

From the third statement:Joey must be in rank 3 3 because Bill is maybe in rank 2 2 or 3 3 , and we know that rank 3 3 is the highest. This means that Bill is rank 2 2 and David is rank 1 1 .

Good, but notice that we don't have to worry about David's rank to solve the problem!

Christopher Boo - 4 years, 1 month ago

Of all the solutions, this is the best solution! \huge\text{Of all the solutions, this is the best solution!}

Monisha Gupta
May 10, 2017
  • the first line states that bill was not the third finalist of the hot dog contest it means that he would be second or first
  • the second line states that david was not the first finalist means he would be third or second
  • the third line states that joey ate more than bill.
  • bill had the possibility of first or second rank and then now when we know that joey is more than bill means bill holds the second rank and joey the first rank

Good line of reasoning and nicely explained. I find this solution very easy to follow.

Pranshu Gaba - 4 years, 1 month ago

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thankyou pranshu

monisha gupta - 4 years, 1 month ago
Venkatachalam J
May 8, 2017

What do the blue cells and X markings mean?

Christopher Boo - 4 years, 1 month ago

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"X" for elimination of the overlapping based on the statement to get the finalized solution. "Blue" for the category.

Venkatachalam J - 4 years, 1 month ago
Noel Lo
May 10, 2017

Or you can just look at the second and last statements! David did not eat the most number of hot dogs and neither did Bill, considering that Bill ate fewer hot dogs than Joey according to the last statement, so Joey is the only possible person who ate the most number of hot dogs.

Good observation. We will still need the first statement if we want to determine who ended in the second and the third places.

Pranshu Gaba - 4 years, 1 month ago
Munem Shahriar
May 10, 2017

Bill did not eat the fewest hot dogs and Joey ate more than him means Joey ate most number of hot dogs.

Right, we can deduce the order from the first and third statements only. The second statement also agrees with the order that we found out.

Pranshu Gaba - 4 years, 1 month ago

Bill did not eat the fewest hot dogs but Joey ate more than Bill.

What does this message convey? Can you be more explicit?

Christopher Boo - 4 years, 1 month ago

it is not a clear answer

monisha gupta - 4 years, 1 month ago
Renz Sibal
Dec 11, 2017

It is known that David did not eat the greatest number of hotdogs, thus we can conclude he is not among the candidates for winners.

The winners could be Bill or Joey.

It is know that Joey ate more than Bill, thus we can conclude that he ate more than both Bill and David.

Thus, the winner is Joey.

Abidur Rahman
May 14, 2017

"David did not eat the greatest number of hot dogs", so Dave is out.

"Joey ate more hot dogs than Bill", so Bill is out.

If Bill did not eat the most and Dave did not eat the most, then Joey must be the one who ate the most

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