Brain teaser brainlock

[SpeedRacer 1]

this was a great brainteaser because at first glance it appears as if they didn't give you enough information to solve it (ie, the speed of the car, speed of the man walking, distance travled etc.)

I'm going to be evil and email this to people.

Speed Racer
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[DJL 235]

Kallend is right.

I found a new one. Will post in new thread:HATS


.

"I encourage all awesome dangerous behavior." - Jeffro Fincher

[FIREFLYR 0]

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This is driving me nuts. Normally I'm good at these things, but I'm experiencing a brainlock and I just don't know how to approach this. How do you go about figuring this one out:


Each day a man's wife meets him at the railroad station and drives him home. One day he arrives at the station an hour early and begins to walk home along the road his wife always takes. She meets him en route and takes him the rest of the way home. Had he waited at the station, she would have picked him up exactly on time. As it turned out, he reached his home twenty minutes early. How long did the man walk?

There is not enough information to answer the question,thats the answer.

"One flew East,and one flew West..............one flew over the cuckoo's nest"
"There's absolutely no excuse for the way I'm about to act"

[labrys 0]

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There is not enough information to answer the question,thats the answer

Huh? The solution was posted.

Owned by Remi #?

[FIREFLYR 0]

Quote

Quote

This is driving me nuts. Normally I'm good at these things, but I'm experiencing a brainlock and I just don't know how to approach this. How do you go about figuring this one out:


Each day a man's wife meets him at the railroad station and drives him home. One day he arrives at the station an hour early and begins to walk home along the road his wife always takes. She meets him en route and takes him the rest of the way home. Had he waited at the station, she would have picked him up exactly on time. As it turned out, he reached his home twenty minutes early. How long did the man walk?

Since he AND HIS WIFE saved 20 minutes, it follows that the wife saved 10 minutes on the outbound trip and 10 minutes on the return trip. So the time at which she met him was 10 minutes earlier than she would normally have been at the station.

Since he started walking 60 minutes before she would have met him at the station, she met him after he had been walking (60 - 10) minutes = 50 minutes after he left the station. QED.

HE IS AN HOUR EARLY TO THE STATION.
HE ARRIVES HOME 20 MINUTES EARLY.
IT DOES NOT SAY HOW LONG IT USUALLY TAKES FOR HIM TO GET HOME.
WE DON'T KNOW HOW LONG IT WOULD TAKE FROM THE PLACE SHE PICKED HIM UP TO THE STATION.(not that it would matter anyway.)

"One flew East,and one flew West..............one flew over the cuckoo's nest"
"There's absolutely no excuse for the way I'm about to act"

[PhillyKev 0]

Umm...did you read the answer that you quoted.

The question was, how long did he walk. The answer and proof is quoted in your post. He walked for 50 minutes.

[labrys 0]

Kallend nailed the logic behind the solution:

Will a numerical solution help?

Take “Ts” as the time the guy's wife usually picks him up. “Te” as the time he usually gets home, and “Td1” as the time it takes for them to drive home.

In the problem, he leaves 60 minutes early (Ts-60) and arrives home 20 minutes early (Te-20). He walks for some of the time “Tw” and his wife drives for some of the time “Td2”

So… when his wife picks him up on time:

Td1 = Te-Ts

When he left early:

Tw + Td2 = Te – 20 – Ts + 60 = Te – Ts + 40 = Td1 + 40

So:

Tw + Td2 = Td1 + 40

If he got home 20 minutes early, then so did his wife. That can only mean that her round trip was shortened by 10 minutes each direction. Therefore Td2 (the time it took her on the return trip when he walked part way) is 10 minutes shorter than the normal drive home (Td1) Or:

Td2 = Td1 – 10

That means that:

Tw + Td1 – 10 = Td1 + 40

Tw = 50.

Time walked equals 50 minutes. You don’t have to know how long it takes him to get home on a normal trip, only that the trip itself was 40 minutes longer than usual.

Edited an error.

Owned by Remi #?