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Anonymous at Sun, 24 Mar 2024 18:40:47 UTC No. 16094627
Can /sci/ do what AI's can't?
A man walks up an escalator. On his way up he counts 50 steps. When he reaches the top, he turns around and sprints down the escalator while it's still moving up. He counts 125 steps on his way down. He runs 5 times as fast as he walks. How many steps are visible on the escalator?
first ai said 68,75, 2nd said 50, 3rd said 75 and the 4th said the the number of visible steps cant be calculated without knowing the speed of said escalator.
Anonymous at Sun, 24 Mar 2024 18:56:19 UTC No. 16094645
>He counts 125 steps on his way down.
This information is irrelevant because on his way down he naturally uses the de-escalator and not the same escalator he used for going up. If he ran the same escalator down into opposite direction, he'd be committing a serious offense. Mathematical thought experiments based on illegal behavior are not worthy of discussion.
sage at Sun, 24 Mar 2024 19:26:11 UTC No. 16094694
>>16094627
velocity of escalator: v
velocity of man: w
total length of escalator: n
He goes up
t = 50 = n/(w+v)
he goes down
t = 125 = n/(w*5-v)
yeah you can't solve this lmao
3 variables and 2 equations
You can't solve this lmao
Anonymous at Sun, 24 Mar 2024 21:07:18 UTC No. 16094844
S1 is steps up: S1=50+2x
S2 is steps down: S2=125-x
S1 = S2
50+2x = 125-x
3x = 125 and x = 25
S1 = 50+2*25=100 and S2=125-25=100
The staircase has 100 steps
Anonymous at Sun, 24 Mar 2024 21:13:15 UTC No. 16094859
>>16094844
>The staircase has 100 steps
that means the escalators goes as fast as he's walking on it. on return he'd just be stuck on the first step, forever, until death.
Anonymous at Sun, 24 Mar 2024 21:14:55 UTC No. 16094863
>>16094859
he runs 5x as fast as his walking speed on the way down tho
Anonymous at Sun, 24 Mar 2024 21:16:49 UTC No. 16094869
>>16094863
ah didn't notice he's running down x5 faster.
🗑️ Anonymous at Mon, 25 Mar 2024 01:25:16 UTC No. 16095255
The result is confusing me but this is my approach:
For sake of simplicity: measure distances and velicities in stairs:
s - velocity escalator
m - velocity man
l - length of escalator in stairs
Time up:
t1 = l / m+s
Man walks distance of:
t1*m = lm/ m+s = 50
Time down:
t2 = l / s-5m
Man walks:
t2*m = lm / s-5m = 125.
We get:
lm = 50(s+m) = 125(s-5m)
Solving the second equation gives you m=9v. Therefore, l*9v = 500v, resulting in l = 55,5... therefore, 56 stairs are visible.
The result feels odd but maybe it should be.
🗑️ Anonymous at Mon, 25 Mar 2024 01:33:10 UTC No. 16095264
>>16095255
Ok, I made an error solving the equation. Actually, v = 9m where m is the speed of the walking man. Then we get lm = 500m, resulting in l= 500.