O.k. Riddle time

wprager wrote:

Tukker wrote:

Tukker wrote:I have two US coins totaling 30 cents. One is not a nickel. What are the coins?

any more riddles?

Tons.

Two trains are traveling along the same track toward each other. The slow train is going at 20 mph while the fast one is traveling at 60 mph. The trains are 40 miles apart. A fly, starts flying from the tip of the fast train, going at 80 mph. It flies until it reaches the slow train, the turns around and flies back, over and over. Assuming the fly can reverse its direction instantaneously, what is the distance the fly will have covered by the time it is crushed between the two trains?

i hate these ones, im not even tryin

Tukker wrote:

wprager wrote:

Tukker wrote:

Tukker wrote:I have two US coins totaling 30 cents. One is not a nickel. What are the coins?

any more riddles?

Tons.

Two trains are traveling along the same track toward each other. The slow train is going at 20 mph while the fast one is traveling at 60 mph. The trains are 40 miles apart. A fly, starts flying from the tip of the fast train, going at 80 mph. It flies until it reaches the slow train, the turns around and flies back, over and over. Assuming the fly can reverse its direction instantaneously, what is the distance the fly will have covered by the time it is crushed between the two trains?

i hate these ones, im not even tryin

40 miles

Amnesia021 wrote:

Tukker wrote:

wprager wrote:

Tukker wrote:

Tukker wrote:I have two US coins totaling 30 cents. One is not a nickel. What are the coins?

any more riddles?

Tons.

Two trains are traveling along the same track toward each other. The slow train is going at 20 mph while the fast one is traveling at 60 mph. The trains are 40 miles apart. A fly, starts flying from the tip of the fast train, going at 80 mph. It flies until it reaches the slow train, the turns around and flies back, over and over. Assuming the fly can reverse its direction instantaneously, what is the distance the fly will have covered by the time it is crushed between the two trains?

i hate these ones, im not even tryin

40 miles

I agree

Tukker wrote:no archive?

What I meant was back when there were "new" puzzles that had not yet made it to the archive. Back in those days there was no google. There wasn't even browsers. I remember searching the web using FTP by e-mail. You'd e-mail your FTP request to a server. Typically your request would consist of commands to open a URL and get a directory listing. When you got the reply you'd fire off another request to go down the directory tree. Eventually you'd find what you're looking for and do a get.

Sorry, that probably has little to do with rec.puzzles, but if you wanted to find the answer it was a lot quicker to just try and work it out.

wprager wrote:

Tukker wrote:no archive?

What I meant was back when there were "new" puzzles that had not yet made it to the archive. Back in those days there was no google. There wasn't even browsers. I remember searching the web using FTP by e-mail. You'd e-mail your FTP request to a server. Typically your request would consist of commands to open a URL and get a directory listing. When you got the reply you'd fire off another request to go down the directory tree. Eventually you'd find what you're looking for and do a get.

Sorry, that probably has little to do with rec.puzzles, but if you wanted to find the answer it was a lot quicker to just try and work it out.

its not very fun to just google it

Tukker wrote:

wprager wrote:A person walks up a hill starting at 8 pm and arrives at the top at midnight.
The next day the same person walks down the hill following the same path, again
starting at 8 pm and arriving at midnight. Is there necessarily a point on
the path where the person is at the same time on both days?

at 10 pm?

He does not walk at a uniform pace but, sure, it could be at 10 PM. The question was whether there was necessarily a common point on the two trips, regardless of whether he sprints or takes a nap during his walk. That's why the up/down hill is introduced, since it makes it pretty obvious he'll walk faster downhill, so he must have stopped along the way.

By the way, the answer is (or at least was) yes.

The explanation goes like this. Plot his trips. The Y-Axis is the time (from 8PM to midnight), and the X-Axis is the path (from point A to point B). One curve/line would go bottom-left to top-right (A,8PM to B,midninght), the other bottom-right to top-left (B,8PM to A,midnight). No mater how you draw the curves (even doubling back) they have to cross, and that would be the common point (same time, same location).

Tukker wrote:

wprager wrote:

Tukker wrote:

Tukker wrote:I have two US coins totaling 30 cents. One is not a nickel. What are the coins?

any more riddles?

Tons.

Two trains are traveling along the same track toward each other. The slow train is going at 20 mph while the fast one is traveling at 60 mph. The trains are 40 miles apart. A fly, starts flying from the tip of the fast train, going at 80 mph. It flies until it reaches the slow train, the turns around and flies back, over and over. Assuming the fly can reverse its direction instantaneously, what is the distance the fly will have covered by the time it is crushed between the two trains?

i hate these ones, im not even tryin

That one's actually simple. You can do it by trying to add-up the infinite sum of the fly's trips, or you can just analyze the situation.

The two trains are 40 miles apart and traveling toward each other at 80 mph (20 + 60). This means that the crash will take place in a half hour. Since the fly is flying at a constant speed (instantaneous reversals), you just have to multiply his flying speed by the time until collision. 80 mph x 0.5 h gives you 40 miles.

wprager wrote:

Tukker wrote:

wprager wrote:

Tukker wrote:

Tukker wrote:I have two US coins totaling 30 cents. One is not a nickel. What are the coins?

any more riddles?

Tons.

Two trains are traveling along the same track toward each other. The slow train is going at 20 mph while the fast one is traveling at 60 mph. The trains are 40 miles apart. A fly, starts flying from the tip of the fast train, going at 80 mph. It flies until it reaches the slow train, the turns around and flies back, over and over. Assuming the fly can reverse its direction instantaneously, what is the distance the fly will have covered by the time it is crushed between the two trains?

i hate these ones, im not even tryin

That one's actually simple. You can do it by trying to add-up the infinite sum of the fly's trips, or you can just analyze the situation.

The two trains are 40 miles apart and traveling toward each other at 80 mph (20 + 60). This means that the crash will take place in a half hour. Since the fly is flying at a constant speed (instantaneous reversals), you just have to multiply his flying speed by the time until collision. 80 mph x 0.5 h gives you 40 miles.

you're the smartest, we get it :D

Tukker wrote:
its not very fun to just google it

Well, as much as it would be fun to catch up to PKC, I've got to stop. If you want more puzzles, just google "rec.puzzles archive". Just fight the temptation to click on the solution link.

wprager wrote:

Tukker wrote:
its not very fun to just google it

Well, as much as it would be fun to catch up to PKC, I've got to stop. If you want more puzzles, just google "rec.puzzles archive". Just fight the temptation to click on the solution link.

lol, i thought you meant googleing the answers :D

Tukker wrote:

wprager wrote:

Tukker wrote:

wprager wrote:

Tukker wrote:

Tukker wrote:I have two US coins totaling 30 cents. One is not a nickel. What are the coins?

any more riddles?

Tons.

Two trains are traveling along the same track toward each other. The slow train is going at 20 mph while the fast one is traveling at 60 mph. The trains are 40 miles apart. A fly, starts flying from the tip of the fast train, going at 80 mph. It flies until it reaches the slow train, the turns around and flies back, over and over. Assuming the fly can reverse its direction instantaneously, what is the distance the fly will have covered by the time it is crushed between the two trains?

i hate these ones, im not even tryin

That one's actually simple. You can do it by trying to add-up the infinite sum of the fly's trips, or you can just analyze the situation.

The two trains are 40 miles apart and traveling toward each other at 80 mph (20 + 60). This means that the crash will take place in a half hour. Since the fly is flying at a constant speed (instantaneous reversals), you just have to multiply his flying speed by the time until collision. 80 mph x 0.5 h gives you 40 miles.

you're the smartest, we get it :D

Yeah, most of the hard ones I ended up "looking up". Just too impatient. But there was one puzzle that I would put in the fairly hard category, which I did without help, and I felt quite good about it. I'm not sure it's in the archive, so here goes:

A camp councilor is on a hike with 8 campers. They get terribly lost until they come to a 4-way intersection of two roads, with a sign post. The sign, which had fallen to the ground, says "Camp 1 hour walk this way". It's getting late, and his only choice is to send scouting parties in each of the four directions with instructions to walk for an hour and come right back to report their findings. Then, he makes a decision based on the findings and leads the troupe to safety before nightfall.

Problem is, one of the campers is a liar. Worse, he doesn't lie all the time, very inconsistent about that. He can obviously trust himself, but he'd need to send three campers down each of the other three remaining paths (if the liar lies the other two in his scouting party would outvote him).

What does he do?

wprager wrote:

Tukker wrote:

wprager wrote:

Tukker wrote:

wprager wrote:

Tukker wrote:

Tukker wrote:I have two US coins totaling 30 cents. One is not a nickel. What are the coins?

any more riddles?

Tons.

Two trains are traveling along the same track toward each other. The slow train is going at 20 mph while the fast one is traveling at 60 mph. The trains are 40 miles apart. A fly, starts flying from the tip of the fast train, going at 80 mph. It flies until it reaches the slow train, the turns around and flies back, over and over. Assuming the fly can reverse its direction instantaneously, what is the distance the fly will have covered by the time it is crushed between the two trains?

i hate these ones, im not even tryin

That one's actually simple. You can do it by trying to add-up the infinite sum of the fly's trips, or you can just analyze the situation.

The two trains are 40 miles apart and traveling toward each other at 80 mph (20 + 60). This means that the crash will take place in a half hour. Since the fly is flying at a constant speed (instantaneous reversals), you just have to multiply his flying speed by the time until collision. 80 mph x 0.5 h gives you 40 miles.

you're the smartest, we get it :D

Yeah, most of the hard ones I ended up "looking up". Just too impatient. But there was one puzzle that I would put in the fairly hard category, which I did without help, and I felt quite good about it. I'm not sure it's in the archive, so here goes:

A camp councilor is on a hike with 8 campers. They get terribly lost until they come to a 4-way intersection of two roads, with a sign post. The sign, which had fallen to the ground, says "Camp 1 hour walk this way". It's getting late, and his only choice is to send scouting parties in each of the four directions with instructions to walk for an hour and come right back to report their findings. Then, he makes a decision based on the findings and leads the troupe to safety before nightfall.

Problem is, one of the campers is a liar. Worse, he doesn't lie all the time, very inconsistent about that. He can obviously trust himself, but he'd need to send three campers down each of the other three remaining paths (if the liar lies the other two in his scouting party would outvote him).

What does he do?

send 3 on the first three paths, than he goes down the last?

Tukker wrote:
send 3 on the first three paths, than he goes down the last?

So the councilor gets back without finding the camp. The three he sent down the other paths all come back saying the same thing. Obviously the liar is lying. Did I forget to say that he doesn't know who the liar is? Sorry. He knows someone is lying (in fact, he's expecting it) but he doesn't know which one.

wprager wrote:

Tukker wrote:
send 3 on the first three paths, than he goes down the last?

So the councilor gets back without finding the camp. The three he sent down the other paths all come back saying the same thing. Obviously the liar is lying. Did I forget to say that he doesn't know who the liar is? Sorry. He knows someone is lying (in fact, he's expecting it) but he doesn't know which one.

Maybe i'm missing something, but didn't you answer you're own question?

There are 9 people total and 4 paths.

Councilor takes path 1
3 of the remaining 8 take path 2
3 of the remaining 5 take path 3
and the last 2 take path 4

In fact, you could probably skip the fourth path and just send 4 on each of the remaining 2...

Tukker wrote:I have two US coins totaling 30 cents. One is not a nickel. What are the coins?

Haha, too easy Tukk, one's a quarter the other is a nickel.

wprager wrote:If 6 cats can kill 6 rats in 6 minutes, how many cats does it take to
kill 100 rats in 50 minutes?

1 cat per rat per minute. It would take 2 cats to kill 100 rats in 50 minutes.

wprager wrote:Yeah, most of the hard ones I ended up "looking up". Just too impatient. But there was one puzzle that I would put in the fairly hard category, which I did without help, and I felt quite good about it. I'm not sure it's in the archive, so here goes:

A camp councilor is on a hike with 8 campers. They get terribly lost until they come to a 4-way intersection of two roads, with a sign post. The sign, which had fallen to the ground, says "Camp 1 hour walk this way". It's getting late, and his only choice is to send scouting parties in each of the four directions with instructions to walk for an hour and come right back to report their findings. Then, he makes a decision based on the findings and leads the troupe to safety before nightfall.

Problem is, one of the campers is a liar. Worse, he doesn't lie all the time, very inconsistent about that. He can obviously trust himself, but he'd need to send three campers down each of the other three remaining paths (if the liar lies the other two in his scouting party would outvote him).

What does he do?

I don't understand this. If the liar is going to get outvoted in his own scouting party, then what is the problem exactly?

Assuming the councilor takes a path, and then he sends the remaining campers on the other three paths, then how does the liar even get his voice heard?

EDIT: I think I understand the question now. Instead of sending parties down all 4 of the paths, he could split up the campers into 3 groups. The councilor and two campers down road 1, 3 campers down road 2, and 3 campers down road 3. If they come back in an hour and none of them have found the campsite, that means road 4 is the only way left to get back. And since there would be more than 2 people per group, the liar would get outvoted.

Have I understood this question right?

PKC wrote:

Tukker wrote:I have two US coins totaling 30 cents. One is not a nickel. What are the coins?

Haha, too easy Tukk, one's a quarter the other is a nickel.

damn, thats either one you get right away or never get