Is it because the outside linear pairs of any polygon will always equal 360 degrees?
@daytonbrownhedgewoodbuilde4932 Says:
I’m so dumb 😣
@m1ch41q Says:
First thought: 3. After a minute of thinking: 4.
@Polaris.comicbook Says:
It is a problem in computer science.
@beethoven3567 Says:
Another way to see that an additional full rotation is needed is to use Archimedes' method of inscribing an n-sided regular polygon into the larger circle. Now roll the small circle around the polygon. Ah, but what happens when it encounters a vertex? Notice that, before the circle can begin rolling on the next side, it needs to first rotate by (2 x pi)/n radians. Having to do this n times in order to make its way back to the starting point, means that it must rotate by a total of n x (2 x pi)/n = 2 x pi radians (in addition to the radians needed to traverse the n polygon sides). Now, as n approaches infinity, the polygon begins looking more and more like the big circle and the number of radians needed to traverse the n sides approaches 3 x 2 x pi. Therefore, in the limit, the small circle must rotate a total of 4 x 2 x pi radians to return back to the starting point on big circle.
@joshua43214 Says:
All these answers are correct for "revolve," but not rotate.
1 is the correct answer
@kellynestegard5208 Says:
A year is NOT precisely 365.25 days. If it was, why do we skip a leap year three times every 400 years
@PreciousBoxer Says:
To think that tests like this determine a person's future and earning potential is both astounding and infuriating.
@PreciousBoxer Says:
Put the smaller circle on the inside of the larger circle and then rotate.
@Khun-z5t Says:
Velocity MINUS V and no one wonders
@danieretief3803 Says:
I wonder how many astronomers have complained about something being wrong and heard "did you remember to account for sidereal day?" from their colleagues
@NikiPetrovAtanasov Says:
It's very easy if you look at those circles as a gears. One is 3 times bigger than the other so I can assume the circle with radius 1 have 10 teeth and the circle with radius 3 have 30 teeth. Considering the rules for gear ratios the smaller one will make 3 revolutions.
It's another story that the question itself is not clearly written.
@Jee-m2m Says:
and then they started to give admission in ivy leagues
@bill-2018 Says:
It can't be three and six seems far too many so I'd guess 9/2.
@freman007 Says:
If point A was fixed then it would have to rotate three times to have the starting points of A and B converge again, but because it's also rotating around B that's a fourth rotation for a total of four full rotations.
@snipergwen Says:
this is so stupid tho. maths is not smthg that returns 7 diff answers to the same problem that js doesn't happen
@micah560 Says:
I know I'm a 32 year old man who graduated with an engineering degree, but I did get a sense of satisfaction when I got 4 before playing the video further. With that in mind if I was rushing on a 25 question test I might have just thought it was 3 because humans always jump to the easy number. I only spent more time on it because the video said it was a trick.
@AllGoodNamesRGone-nykw Says:
0:47 Maybe I'm misunderstanding something. Even though the circle A "rotated" whatever times to "rolls" around circle B, wouldn't it be 1 revolution for center to reach the initial point?
Considering that the centre of A will travel 2π(4r) to reach back at the same point and 1 revolution, as I know, is 1 coverage of orbit path.
Edit: 6:58 Ah, I wasn't wrong in my understanding...
@marcmarc4776 Says:
So what's the answer? Im not watching 16mins to figure out this
@MemoirsofaGamer1982 Says:
My brain isn’t wired for this; even watching this video felt like my brain hit an invisible wall.
It’s a good job I have other talents. 😂
@packnanimous Says:
No, B is not necessarily wrong. It depends on how you define a revolution of circle A. With respect to horizontal (as demonstrated in video), it is 4 revolutions. But w respect to tangential of circle B, it is 3.
And I am one who actually did find, and report, an error on a PSAT question. But that was back in the 80s, so take it for what it's worth 🤷♂️.
@superllama666____________3 Says:
9
@Roadkill3120 Says:
In 80 days around the world
@cerad7304 Says:
Finding the answer by cutting out circles probably explains why scissors are not allowed while taking the test.
@peterhughes4762 Says:
I took SATs in 1982 also. Hates those things. Words that we would never use and abstract math nonsense that was not useful. I didn’t get any scholarships but I became an engineer with a higher GPA than some who did. That said, no standard these days is crazy too.
@allisen5125 Says:
what kind of education is that? not that, what I want for any child in the world. why this pressure? I really hope stuff like this will disappear soon.
@mparento Says:
One more way to get an idea that the answer is not 3 is to suppose that the B circle is just a point. It is then obvious that A would have to revolve around B to come back to its original position. The answer could not be zero.
@volkov2000 Says:
It’s even more interesting if you take that linear path and instead of making a circle, make it into a tight spiral with say 4 “twists”. Then, rolling the smaller circle along the spiral of the same length will yield even more rotations. So, the number of rotations is path-dependent.
@Maleko5267 Says:
9
@trappedoctopus Says:
SAT scored me as someone who would not do well in college. I’m now a resident training for board certification in family medicine. SAT is and has always been a scam.
@catniphill Says:
My seventh-grade English teacher once gave us a spelling test in which she read out “antidote” and then insisted it was spelled “anecdote.”
@earlymusicus Says:
Wellthen, what’s the point of that question, since all the answer choices are wrong?
@tamarlindsay8382 Says:
The "rolling coin around another coin" is a false demonstration. The significant factor is that the point on the edge that contacts the edge of the stationary coin is only halfway around at the halfway point. The use of the coin face is a distraction. The rest of the demonstration can be assumed to be a lie as well.
The astronomy part is entirely irrelevant to a pure geometry problem.
@riboflavin-b2413 Says:
The wording of this question is quite bad.
@stephenanderle5422 Says:
I wish they would go back to these tests again. Then the teacher could see how good of a job they are doing. It would raise the IQ level of this country. Back up to what it used to be.
@DuolingoSux Says:
The SATs were always sloppy and over-rated. The English testing was abysmal.
@user-dd1rg7sd9l Says:
Suppose EVERYTHING you thought you knew was WRONG?
@robertread3046 Says:
Your over thinking this this is a great problem you have a 3 to 1 gear ratio
@jerrywyant5409 Says:
What of you didn't take it?
@LindaB651 Says:
I remember getting ONE college test question marked wrong in a math class, and I contested it, because my answer was correct, but the question was ambiguous. When pressed, the instructor agreed that yes, my answer was correct, but it wasn't the answer they were looking for (although they hadn't clarified which answer they'd required.) The instructor then asked why it mattered to me, since it was my only wrong answer on that test, and I'd still be getting a high grade. I told him it was a matter of principle- I want what I'd earned, PLUS, what about students having a hard time, maybe failing because of ONE badly explained problem giving them a failing score.
The people making the tests have forgotten what it's like to be TAKING the tests!
@User_-_8472_-_resU Says:
Paused at 0:52 - my answer is (B) 3.
0:59 - Damn...
In my defense though, I got four the first time. When that wasn't an option I just assumed I was wrong.
@hughkills Says:
Spoiler, it's because the center of the outer circle moves further than the edge of that circle (when moving in a circle around it). You have to draw a 3rd circle that has radius rC1+rC2.
@TexasOutlaw1 Says:
Instructive mathematically..... but "Space" is fake and gay!
@MrBurninCross Says:
The gear on the left has C of πd or 2π, and the other has a C of 6π, or of 1 to 3. Ans is B., 3?
@BluesImprov Says:
This "question" has NOTHING to do with the ability of someone to become wise and make excellent decisions in life. NO, it doesn't. To me, the art of being wise, is the art of knowing what to overlook. Like stupid questions such as this one!
@andiehyde3714 Says:
3.
@theGoogol Says:
I would've answered 9/2 🤐
@IAmWilliamJLepetomane Says:
This video made me feel dumb. 😂
I was lost from just about the beginning.
@chloboxoxo Says:
wait i feel so goated
@adamrussell658 Says:
Weird thing is, if the answer really was 3 then the problem would be too easy to be on an SAT.
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