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Mr. A, B, C decided compete in athletics against each other. They competed in few disciplines.

Winner got x points, second y points, last z points: x>y>z. x,y,z are integers. There were no draws(ties) in any discipline.

Mr. A scored 22 points, Mr. B and Mr. C scored 9 points. Mr. B won the long jump. Who was the second in the 1/4 mile run?

I made a model:

A - 22 points B - 9 points C - 9 points

B won the long jump

$$ MAXPOINTSTOSCORE = 22+9+9=40 $$

I can't guess 3 integers(x,y,z) which would match this data.

Yoda
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  • I think you have to restrict x, y, and z to (non-zero) natural numbers, not integers. Otherwise there is a solution x=3, y=1, z=0 and: A won 6 events and came second in 4, and each of B and C won 2 events, came second in 3, and came third in 5. That case does not reveal enough information to answer the question. Furthermore, if admitting all integers, there might even be solutions where y and/or z are less than 0, but I don't know if that's the case. – Celada Oct 13 '14 at 02:22

2 Answers2

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The answer is Mr.C. In detail following things happened:

  1. They competed in $5$ disciplines.
  2. The values of $x,y,z$ are $(5,2,1)$ respectively.
  3. Mr. A came first in $4$ disciplines and second in long jump, thus collecting $4\times5+2=22$ points. Note that this means that Mr. A won the 1/4 mile run.
  4. Mr. B came first in the long jump and then (necessarily) finished third in all other disciplines, thus collecting $5+4\times1=9$ points. Note that this means that Mr. B finished third in the 1/4 mile run.
  5. Mr. C came third in the long jump and (necessarily) second in every other discipline. thus collectiong also $1+4\times2=9$ points.

The justification is presented below.


Denote with $N$ the number of disciplines in which they competed. Of course $N$ is an integer. Then you know that $$N(x+y+z)=40=5\cdot2^3$$ which means that $$N\in\{5,10,20, 2,4,8\}$$ and similarly $$x+y+z \in \{5,10,20,2,4,8\} $$But since $x>y>z>0$ then you have that $x+y+z\ge3+2+1=6$ so that $$x+y+z\in \{8,10,20\}$$ and therefore $$N \in \{5, 4, 2\}$$ Moreover, since Mr. B has won at least one discipline and has $9$ points then we have that $x\le 8$ because they competed in at least two disciplines (see values of $N$). But then it is impossible for Mr. A to have been able to collect $22$ points if there are only two disciplines! So, the possible values of $x+y+z$ and $N$ are further reduced to $$x+y+z\in\{8,10\}$$ and $$N\in\{5,4\}$$ respectively. Now, since there are only two cases, we can treat them separately

  1. Case: $N=5, x+y+z=8$. Then necessarily $x=5,y=2,z=1$.
  2. Case: $N=4, x+y+z=10$. Then $x=7,y=2,z=1$ or $x=6, y=3, z=1$ or $x=5, y=4, z=1$ or $x=5, y=3, z=2$. Now, we take all these triplets to see if we can create the numbers $22$ and $9$ with combinations of $4$ of the given values.

    • If $x=7$ then necessarily Mr.A won $3$ disciplines and came 3rd in the remaining 4th discipline. But, then Mr. B won the 4rth discipline (long jump) so that Mr. C won no discipline. But then the best Mr.C can do is to collect $4\cdot y=4\cdot 2=8<9$ points. So this case is excluded.
    • If $x=6$ then you cannot reach $22$ with any combination of $x,y,z$ (using $4$ of them). So this case is also excluded.
    • If $x=5$ similarly. So the last two triplets of the case $N=4$ are excluded!

In sum, we found that the only admissible values of $x,y,z,N$ are $$x=5, y=2, z=1$$ and $N=5$. Now, it is obvious that Mr. A won 4 out the 5 disciplines and came second in the remaining one, which was long jump and which was won by Mr. B. But, then Mr.B collected in total $9$ points by finishing third in every other discipline, because in any other case he would have collected more than $9$!! So Mr.C is the one who came second in every other discipline except for the long jump where he came third.

Jimmy R.
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I think it's C. Let the points be 5 for first, 2 for second, and 1 for third, with 5 events total. Then A won all events except the long jump, where he got second. B was last in all events except the long jump, which we know he won. And C was second in every event except the long jump, where he was last. So if C was second in everything else, he must have been second in the 1/4 mile run.

soakley
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