Skip to content

Topic: Puzzle 11

+

Puzzle 11

From Message
icon Damo
+
Puzzle 11
Suppose that the swift Achilles is having a race with a tortoise.

Since the tortoise is much slower, she gets a head start. When the tortoise has reached a given point A, Achilles starts.

But by the time Achilles reaches A, the tortoise has already moved beyond point A, to point B. And by the time Achilles reaches B the tortoise has already moved a little bit farther along, to point C.

Since this process goes on indefinitely, Achilles can never catch up with the tortoise.

How can this be?
icon VALLEY
+
Puzzle 11
Achilles is moving at the same speed as the tortoise?
icon Jon
+
Puzzle 11
Achilles is an asymtote. He never actually reaches the tortoise ever!
icon Rich_Rocks
+
Puzzle 11
Achilles is also a tortoise.
icon Sweetmadness
+
Puzzle 11
I don't know....why do you ask??
icon Damo
+
Puzzle 11
The question does say that Achilles is 'swift' and that the tortoise is 'much slower'
icon VALLEY
+
Puzzle 11
The infinite series of fractions involved in e.g., the Racetrack, has a finite sum: (1/2 + 1/4 + 1/8 + ...) = 1.

Hence one will of course reach the end of the track.

Of course half the length, plus one fourth, plus one eighth, and so on, add up to the whole length. And that's just the point. The whole length contains an infinite number of finite parts. In order to traverse it, therefore, a runner would have to complete an infinite number of tasks. But how can such a thing to be possible? It isn't!

Is that right?
icon Damo
+
Puzzle 11
Pretty much along the right lines.

What you haven't done is explain it in terms of Achilles and the tortoise
icon VALLEY
+
Puzzle 11
Well you know what i mean!
icon spookylukey
+
Puzzle 11
Achilles will pass the tortoise after a finite amount of time, because he is going faster.

You can of course break this time into an infinite number of steps, each step getting smaller and smaller, as described, but this doesn't make any difference - you can still complete a infinite number of things in a finite time.
icon Jon
+
Puzzle 11
asymtote

You un cultured muppets
icon VALLEY
+
Puzzle 11
I think my answer is right...........hang on, i alreadd wrote this message. Someones erased it! HEY!!!!
icon Jon
+
Puzzle 11
Actaully I answered it in one word.... but no... I was ignored!
Login to post a message.