Riddle of the Day

[DnD]

Originally Posted by wmtire

If we are going to throw fun riddles into this discussion, I have a personalized one.

Herk, Turbs, RVChick, and B47 are walking back to their campsite late at night after hiking most of the day. The path that they are following is not lit, but luckily they have one flashlight to share. Along the way, they come to a long, shaky, bridge that they must cross to get over a river. Turbs and RVChick are runners and love the thrill of running across the bridge, so Turbs can cross the bridge in 1 minute, but RVChick is a little slower and can cross in 2 minutes. B47 refuses to run across the bridge, so it takes him 5 minutes to walk the bridge. Herk has a twisted ankle and has to walk slowly, so it takes him 10 minutes to cross the bridge. Only two people can cross the bridge at once; otherwise it might collapse from the weight. If two people cross the bridge at once, they walk or run the bridge at the rate of the slower person so that they can share the flashlight. Anyone crossing the bridge must have the flashlight with him or her; otherwise they cannot see and might fall off of the bridge. The flashlight must be walked back and forth because the bridge is too long to throw the flashlight across.

What’s the shortest time it will take for Turbs, Herk, RVChick, and B47 to all get cross the bridge?

18 minutes...they wait till daylight when they dont need the flashlight.

[TURBS]

Originally Posted by DnD

18 minutes...they wait till daylight when they dont need the flashlight.

I'm not spooning b47 while we wait either get that right of ur head!

[B47]

Originally Posted by f1100turbo

I'm not spooning b47 while wait either get that right of ur head!

THat is for darn sure!!!!!

[ependydad]

Originally Posted by DnD

MPH IS a time limit. It measures distance within an hours time.

In my example of a 1 mile track. To average 60 MPH that allows you 1 minute to circle the track. i.e 1 mile per minute = 60 miles per hour. At 30 MPH it takes you 2 mins to complete a mile or 1 minute to complete 1/2 mile. Therefore you ran out of time to complete a mile in 60 seconds or 60 MPH.

I used 1 mile as a simple example...this works out regardless of track length because no matter how long the track...you will have used all the time to drive 1/2 the track needed to average 60 for the whole track.

My brain hurts.

[DnD]

Originally Posted by ependydad

My brain hurts.

Yeah math does that to me too! My previous job at the company I work for was developing the software that insurance actuarials use. That $%#&* will give you a headache like you can believe! Made the stats class I took in college look like 1st grade math.

[B47]

Knowing Turbo - he probably had too many beers and drops the flashlight into the river and three of us, B47, RV Chick and Turbo jump into the river trying to retrieve it. But none of us can swim.

Herk being the man he is, tries to save all of us and being the leader he is, tries to rescue RVChick first, but is unable to when Turbo pushes her aside yelling "save me first - save me first"

Thus none of us ever got across that darn bridge - Thanks to Turbo.

[wmtire]

Originally Posted by DnD

18 minutes...they wait till daylight when they dont need the flashlight.

LOL They can't wait till daylight because the margaritas were waiting, and DnD was grilling steaks

18 isn't quite correct, but close

[QCCowboy]

Originally Posted by wmtire

If we are going to throw fun riddles into this discussion, I have a personalized one.

Herk, Turbs, RVChick, and B47 are walking back to their campsite late at night after hiking most of the day. The path that they are following is not lit, but luckily they have one flashlight to share. Along the way, they come to a long, shaky, bridge that they must cross to get over a river. Turbs and RVChick are runners and love the thrill of running across the bridge, so Turbs can cross the bridge in 1 minute, but RVChick is a little slower and can cross in 2 minutes. B47 refuses to run across the bridge, so it takes him 5 minutes to walk the bridge. Herk has a twisted ankle and has to walk slowly, so it takes him 10 minutes to cross the bridge. Only two people can cross the bridge at once; otherwise it might collapse from the weight. If two people cross the bridge at once, they walk or run the bridge at the rate of the slower person so that they can share the flashlight. Anyone crossing the bridge must have the flashlight with him or her; otherwise they cannot see and might fall off of the bridge. The flashlight must be walked back and forth because the bridge is too long to throw the flashlight across.

What’s the shortest time it will take for Turbs, Herk, RVChick, and B47 to all get cross the bridge?

17 minutes

Turbs and RV Chick run across - 2 min
RVChick runs back - 2 min
B47 and Herk walk slowly across - 10 min
Turbs sprints back - 1 min
Turbs and RVChick run across - 2 min

so 2+2+10+1+2 = 17 min

[DnD]

Originally Posted by wmtire

LOL They can't wait till daylight because the margaritas were waiting.

18 isn't quite correct, but close

Oh duh...10 mins. I missread the two at once. If it was daylight that is

[wmtire]

Originally Posted by QCCowboy

17 minutes

Turbs and RV Chick run across - 2 min
RVChick runs back - 2 min
B47 and Herk walk slowly across - 10 min
Turbs sprints back - 1 min
Turbs and RVChick run across - 2 min

so 2+2+10+1+2 = 17 min

And QCCowboy is a winner. 17 it is. Most people get 19 for an answer to it.

You win an all expense paid forum post of your liking.

[ependydad]

Originally Posted by DnD

Yeah math does that to me too! My previous job at the company I work for was developing the software that insurance actuarials use. That $%#&* will give you a headache like you can believe! Made the stats class I took in college look like 1st grade math.

Funny! I worked on a system to assist payroll at a call center that did surveys after a hospital stay. The call center reps would get their base pay and then bonuses based on the number of calls, duration of those calls and the outcomes of the call (completed surveys, partial surveys, times to call back, etc.). I was getting data dumps out of the phone dialing system for each rep and then had to slice it into a database with their bonus pay calculated. That math was crazy. My requirements were an Excel sheet that "Bob" used to do it all by hand with formulas. It took a few of us to figure out the actual rules and then a couple of us to code them up. Oh and they wanted it done in a language that I had no familiarity with- it was what the company wanted to move to and since we were "consultants" we were to guide them (even after I told them they were my first in that language- the "consultant" title won). Crazy times!

Oh and let me tell you about my recent foray into iOS development... sigh.

[DnD]

Originally Posted by wmtire

And QCCowboy is a winner. 17 it is.

You win an all expense paid forum post of your liking.

Congrats QC!

So what was your guess on herk's riddle?

[DnD]

Originally Posted by ependydad

Funny! I worked on a system to assist payroll at a call center that did surveys after a hospital stay. The call center reps would get their base pay and then bonuses based on the number of calls, duration of those calls and the outcomes of the call (completed surveys, partial surveys, times to call back, etc.). I was getting data dumps out of the phone dialing system for each rep and then had to slice it into a database with their bonus pay calculated. That math was crazy. My requirements were an Excel sheet that "Bob" used to do it all by hand with formulas. It took a few of us to figure out the actual rules and then a couple of us to code them up. Oh and they wanted it done in a language that I had no familiarity with- it was what the company wanted to move to and since we were "consultants" we were to guide them (even after I told them they were my first in that language- the "consultant" title won). Crazy times!

Oh and let me tell you about my recent foray into iOS development... sigh.

I was a software engineer for 10 years till I made the mistake of speaking English instead of Tech. They made me a Project Manager. Not so bad though as I am a Program Mgr now LOL

[QCCowboy]

Originally Posted by DnD

Congrats QC!

So what was your guess on herk's riddle?

Thanks! I actually guessed it was not possible.

[DnD]

Originally Posted by QCCowboy

Thanks! I actually guessed it was not possible.

You did...reading AND comprehension are not my strong suit...obviously!

[Herk7769]

Originally Posted by RoadTrip

I'd like a hint to know if I'm on the right track.

If you go 90 on the second half, the average speed is 81. Am I right so far?

Nope.

The hint: Assume a 2 mile track to make the math easier.
The actual track can be any length.

Assume Instant acceleration to the speed you need to average 60 MPH

[Herk7769]

Originally Posted by QCCowboy

It is not possible to average 60 mph.

Correct

[ependydad]

Originally Posted by herk7769

Correct

Sigh- can you try re-explaining why it's not possible? I'm slow.

[Herk7769]

Originally Posted by F.R.O.G.

You're going to get a lot of people swearing that the correct answer is 90.

The fact it, it's a physical impossibility (although since you can accelerate instantaneously, anything might be possible). Now for people to figure out why.

D=RxT

OK, since everyone has figured it out.
HOLY COW I JUST LOOKED AT ALL THE POSTS!!!!!

You would need a Star Trek Teleporter at the 1/2 way point since all the available time to average 60 MPH was used up getting to the half way point at 30 MPH.

Example:

Assume a 2 mile track to keep it simple.

At 30 MPH traveling 1 mile takes 1/30th of an hour or 2 minutes

To average 60 MPH for 2 miles takes 2/60th of an hour or 2 minutes

Since the 2 minutes have already been driven, it is impossible to drive fast enough to drive the last mile in zero minutes.

[Herk7769]

New riddle - Same as the old riddle except:

Drive first half at 45 MPH - How fast on the second half to average 60 MPH.

A FREE Herkbrary DVD to first one to PM me the correct answer.