The worlds first riddle!

Try:
TWELVE SOLDIERS
+/-0.5 hours will cover it, but you're moving in the wrong direction relative to your previous answer.

New problem for MOU:

Twelve pacificists had to get to a place twenty-five miles distant with the quickest possible dispatch, and all had to arrive at exactly the same time. They requisitioned the services of a man with a small car.
"I can do ten miles an hour," he said, "but I cannot carry more than four men at a time. At what rate can you walk?"
"All of us can do a steady three miles an hour," they replied.
"Very well," exclaimed the driver, "then I will go ahead with four men, drop them somewhere on the road to walk, then return and pick up four more (who will be somewhere on the road), drop them also, and return for the last four. So all you have to do is keep walking while you are on your feet, and I will do the rest."

They started at noon. What was the exact time that they all arrived together

PRISM
516 sq ft

ah damn.... Now I have to think, and I hate too much thinking...

Let's see....

He takes four and drives them for 13 miles, then he goes back 7 miles, and pick those that are exactly there....uff...my head already hurts ....
Then he goes 13 miles with them...leaves them on 19 mile mark, and comes back to 12 mile to pick last four...huh....I am confused
So...then he goes another 13 miles with them and leaves them "home", and goes back 7 miles - oh, here they are, as well as those first four...while remaining four are....there? I am too confused at this moment, but I think they are
So, he drove 53 miles, and since he drives 3 miles in 0.33 of an hour it means they arrived at 5.20

And I'll kill someone if I'm not correct

5.28

5.20 man...it has to be or I will...I will....

5:28
5:20 but closest

MOU had it right up to and including "So, he drove 53 miles." His calculation breaks down after that.

I'm glad MOU is in Hrvatska and nowhere near, um, uh, Nova Scotia. Yeah, that's where I am.

Got it! Said Try, posting from Timbuktu. It is 5.16pm

What you have to remember is, soldiers have a heavy kit to carry. Not like those ?'Pacific' types. :wink:

hm...it seems I forgot basic math
He drives 10 miles per hour, or 1 mile per 6 minutes...
Therefore, it should be 5.18 I think, and not 5.16 try

Hi MOU! Long time no read.

I make the answer 5:12pm by the way.

MOU gets it right and doesn't have to kill anybody (I lied about Nova Scotia).

Would Try or Adrian like to explain 5:16 or 5:12?

30% of 60 is 18 not 12....

The mighty Croat is indeed correct.

Try was looking for a simple formula. Here's the best I could do for the general case of N groups of people (N=3 for the problem that was posed).

Dw = Distance each person walks
Dd = Distance each person drives
Dt = Total distance to be covered
Rd = Rate while driving
Rw = Rate while walking
Tt = Total time elapsed
N = Number of people (groups)

Dw = 2(N-1)RwDt/[(2N-1)Rw+Rd]
Dd = Dt-Dw
Tt = (Dt/Rd)[(2N-1)Rd+Rw]/[(2N-1)Rw+Rd]

First person rides Dd, then walks Dw.
Second person walks Dw/(N-1), rides Dd, then walks Dw(N-2)/(N-1).
Third person walks 2Dw(N-1), rides Dd, then walks Dw(N-3)/(N-1).
etc.

"I was walking along the road at three and a half miles an hour," said Mr. Pipkins, "when the car dashed past me and only missed my by a few inches."
"Do you know at what speed it was going?" asked his friend.
"Well, from the moment it passed me to its disappearance round a corner I took nineteen steps and walking on reached that corner with two hundred and sixty-six steps more."
"Then, assuming that you walked, and the car ran, each at a uniform rate, we can easily work out the speed."

Weary Willie went up a certain hill at the rate of two miles per hour and came down at the rate of six miles per hour, so that it took him just four hours to make the double journey. How far was it to the top of the hill

A man set out at noon to walk from Appleminster to Boneyham, and a friend of his started at 1:20 P.M. on the same day to walk from Boneyham to Appleminster. They met on the road at 2:24 P.M., and each man reached his destination at exactly the same time. Can you say at what time they both arrived

Adrian has PM'd a correct answer to the speeding car problem.

Weary Willie went up a certain hill at the rate of two miles per hour and came down at the rate of six miles per hour, so that it took him just four hours to make the double journey. How far was it to the top of the hill

distance is 6 miles

A man set out at noon to walk from Appleminster to Boneyham, and a friend of his started at 1:20 P.M. on the same day to walk from Boneyham to Appleminster. They met on the road at 2:24 P.M., and each man reached his destination at exactly the same time. Can you say at what time they both arrived

Isn't this impossible to tell?? We don't know what speed they are walking at....... is it the same??

"MOU gets it right and doesn't have to kill anybody" (Time 5.18)

Congratulations to the ?'Old World'. Who said, violence does not pay?



"Would Try or Adrian like to explain 5:16 or 5:12"

?'Typo' My 5.28. should have read 5.18. :wink:

What about a stop for gas. The ?'turn around' for the pick-up, wind direction etc


The other reason is as MyO said, "He takes four and drives them for 13 miles, then he goes back 7 miles,"

I stopped on the two hour (back 7 miles (7) mile) mark and then went into fractions of car/people converging within the mile band. It should of cause have been on the (6) mile two hour mark.


Still the good news is I was closer than Adrian, oh life is sweet.



Mark your formula would work just fine. It was to deal with the confusion raised with the car/people within a mile band.

Mark, "Adrian has PM'd a correct answer to the speeding car problem"

Yeah, I got one as well, lucky guess.


Bizarre

"Isn't this impossible to tell?? We don't know what speed they are walking at....... is it the same??"

Hi Bizarre, welcome to the ?'Mad House'. What Mark failed to tell you is; The guys from Appleminster have ?'Blue' eyes, and those from Boneyham, ?'Brown'. The calculation is now simple. I hope that helps.

"Isn't this impossible to tell?? We don't know what speed they are walking at....... is it the same?? "

Their speeds are certainly not the same. However, they are constant. Also, after you've solved the problem, you still won't know their speeds or the distance.

One more thing: Watch out for Try - he's sneaky. It's the Boneyham guys who have the blue eyes.

magnum
"distance is 6 miles "

Mark, "One more thing: Watch out for Try - he's sneaky. It's the Boneyham guys who have the blue eyes."

?'Blue' was a clue. Give the letters a numeric value. Add the first three, divide by the forth and the result should be the answer in hours. :wink: