Brain Teaser # 7 (This is for 62 250 GTO)

Ok Smart Guy. Put on your thinking Touque and figure this one out!

Rob Lay's rich uncle "Uncle Rich" owns a famous breeding stable. It has a private race track that has five lanes. Uncle Rich has 25 horses and wishes to know which are the three fastest. What is the least number of races needed to be run to find the answer?...And explain your answer so we all know you are not guessing!

 

6

 

You only need to run five races, any decent private race track will have the timing capabilities to record the times of the horses and you can then simply compare the times to find the fastest three.

Logic be damned when we have technology!

 

Explain your answer Armen!

I agree, 6. 25 horses, 5 lanes, 1 horse per lane. So 5 horses per race if all lanes are filled, which when all 25 horses race, there are 5 winners. Then those 5 winners race again for the final winner, which comes out to 6.

After all that, I hope I'm right.

 

No that answer can't be correct because the 2nd place finisher in one of the first five races may be faster than the 1st place finisher in one of the other five races.

 

Dang!! I guess I was thinking of a race 200 years ago

 

Oh, sorry, I read the question problem wrong. I didn't see it say the THREE fastest, instead I thought it said the fastest. Sorry, but no madder what, your answer was better.

 

.....and speaking of Jack in the Box.................

DL

 

8

 

A lot, since you must make sure each horse has race each other.
21 races get you 21 winners and 4 losers. (each time the winner is selected, and the 4 losers race against a newcomer). Again and again until 5 are left, I guess. So this would be 75 (21+17+13+9+5+1) races. Sounds like an awful lot ... but you'd be sure you have the 3 (5, actually at the last race) fastest horses. There has to be a quicker way.

 

Ha some one my age

 

You race 5 random race 1 20 left

You keep fastest 3 and get race 2 more 18 left

You keep fastest 3 and get race 3 more 16 left

You keep fastest 3 and get race 4 more 14 left

You keep fastest 3 and get race 5 more 12 left

You keep fastest 3 and get race 6 more 10 left

You keep fastest 3 and get race7 more 8 left

You keep fastest 3 and get race 8 more 6 left ....

not fastest way...:/

You keep fastest 3 and get race 9 more 4 left

You keep fastest 3 and get race 10 more 2 left

You keep fastest 3 and get race 11 more 0 left

 

10

You race 5 random race, and repeat with the remainder everytime. You end up with 5 races with 3 winners each and thus only 15 horses left at the cost of 5 races.

Now with the winners you have the following:

You repeat with the winner set for 3 races. You will get a set of 9 horses left at the cost 3 races.

net 8

repeat again and you will have no horses left at the result of zero. 10 is the result.

Getting better. Still not at it yet.

 

Yahhhhhhhhhhhhhh! I'm here.
Give me a minute. or 2,3,4,5.

 

9 Races:

Again as above break the group into 5 sets of 5 and have your 5 sets of 1-2-3s. 5 races done.

Now with your 15 horses (5 sets of 1-2-3s, choose a set and have them race against the next set of 1-2's and repeat until all the 1-2's are done. 9 Races total. The end is the best of the best so to speak. Only problem is that that the stupid 3rd can be fasterakasjdrkawjjfakefkasekas

Nevermind.

 

Race #1 race horses 1-5
Race #2 race horses 6-10
Race #3 race horses 11-15
Race #4 race horses 16-20
Race #5 race horses 20-25
OK, that's 5 races and now you have the 5 fastest horses.

Race #6 race said 5 fastest horses.
OK. That's 6 races and now you have the fastest horse. {Which I will buy from Rob on Tuesday.}

Race #7 race the 2nd and 3rd horses from the "final five" in race 6. In that same race add, the 2nd and 3rd horses from the 1st race that the "fastest horse" was in.
{{{Do you follow me?}}}}
That's 4, now add the second horse from the first set of races that was in the 2nd fastest horses race. There, that's 5 horses in race #7.
{{{Do you guys need a diagram? I'm not kidding, I'm even getting mixed up writing this.}}}

And the two top horses in race #7 are the 2nd and 3rd fastest horses out of the whole lot.
Whew. I think that's right. And if Peters want a drawing of, I will post it Tuesday morning.
I don't even know if this is right, but it sound like I covered all of the bases.

 

Yeah I'm right. Up at 6:30 am, it's now 12:22 am. EEK!
Im off to bed.

 

I'm sticking with 5 races by using 5 stopwatches, a piece of paper and a pencil.

 

I agree with Eos, you have to think outside the box.

I have one sorta, apparently some companies ask this question to test the thinking skills of prospective employees. so here it goes.

You are driving down a dark road with you car that can only fit one other person. Its pouring rain and at a bus stop you see, your best friend, the woman of your dreams, and someone on the verge of death. What would you do?

 

Um I think you left a race out, because you don't have a number for the race of the 2nd fastest horses.

Code:

First Five Races, and how they finished.    Then we race the 1st and 2nds
1                                                         1     The fastest Horse
2                                                         6
3                                                         11
4                                                         16
5                                                         21
-                                                         -
6                                                         2        
7                                                         7          
8                                                         12
9                                                         17
10                                                        22
-                                                          -
11                                                        At this point we know that 6 beat
12                                                        7 and that 11 beat 12 and etc...
13                                                        We also know that 6 beat 11, 11
14                                                        beat 16 etc... Thus the only two 
15                                                        horses that are competeing for
-                                                          2nd and 3rd are horses #2 and 6
16                                                        -
17                                                        2 The winner of this race is the 
18                                                        6 2nd fastest horse and the loser 
19                                                           is the 3rd fastest.
20                                                        -
-
21
22
23
24
25

So that makes for 8 races

*sidenote* Listening to Phil Henry during this write up.

Fake Guy "Crystal, Filet Mignon, Fish or beef?"
Crystal: "I don't know, Fish"
Fake Guy: "OH MY GOD *barfing noise*"

 

If he is on the verge of death, obviously I can't get himto the hospital in time so I call 911 and let them know, get the girl and pay for my friends bus-fare

 

close but nope. you want to find the best possible outcome.

 

Well since it says its raining, can I then assume the guy is on the verge of death because of hypothermia? Therefor I stick the near dying guy next to the exhaust pipe, pay for the guys bus fair and lean back the passanger seat in the car and get the girl while we all wait for the bus.

Another possible good solution is have my best friend drive the near dying guy to the hospital while I keep the girl warm while waiting for the bus.

 

o man i past 300 posts, i am so cool

 

got it