Chinahand Posted June 27, 2019 Share Posted June 27, 2019 This is from a US SAT exam. The fact is not a single person got it right. There is a reason for that. Think about Phileas Fogg and Passpartout and how many days and nights they experienced on their journey around the world. So, how many times will the small circle rotate? Ignore the multiple choices and just do the maths. Quote Link to comment Share on other sites More sharing options...
woolley Posted June 27, 2019 Share Posted June 27, 2019 Well it should be 3, but I've a terrible feeling you are going to tell us why it isn't.............. Quote Link to comment Share on other sites More sharing options...
dilligaf Posted June 27, 2019 Share Posted June 27, 2019 9 Quote Link to comment Share on other sites More sharing options...
Chinahand Posted June 27, 2019 Share Posted June 27, 2019 And if the circles are the same radius? Quote Link to comment Share on other sites More sharing options...
dilligaf Posted June 27, 2019 Share Posted June 27, 2019 4 minutes ago, Chinahand said: And if the circles are the same radius? 1/2 Quote Link to comment Share on other sites More sharing options...
Chinahand Posted June 27, 2019 Share Posted June 27, 2019 Imagine if the coin was rolled on a flat surface the same distance. How many times would it rotate then? Quote Link to comment Share on other sites More sharing options...
dilligaf Posted June 27, 2019 Share Posted June 27, 2019 (edited) 10 minutes ago, dilligaf said: 1/2 5 minutes ago, Chinahand said: Imagine if the coin was rolled on a flat surface the same distance. How many times would it rotate then? 1 My response of 1/2 was based on 2 ten pence coins. I realise now that I messed up by having them start the same way up, if you know what I mean. ( or did I mess up ? ) Edited June 27, 2019 by dilligaf Quote Link to comment Share on other sites More sharing options...
woolley Posted June 27, 2019 Share Posted June 27, 2019 5 minutes ago, Chinahand said: Imagine if the coin was rolled on a flat surface the same distance. How many times would it rotate then? Until it fell off the end of the flat surface. 1 Quote Link to comment Share on other sites More sharing options...
woolley Posted June 27, 2019 Share Posted June 27, 2019 C'mon, China. Spill the beans, for goodness' sake. 1 Quote Link to comment Share on other sites More sharing options...
Chinahand Posted June 28, 2019 Share Posted June 28, 2019 Too tired then. Too busy now but the point to make is if it was three times on the flat what additional effect happens when going round a circle. Quote Link to comment Share on other sites More sharing options...
Chinahand Posted June 28, 2019 Share Posted June 28, 2019 Hope there are enough hints there!! Quote Link to comment Share on other sites More sharing options...
Bobbie Bobster Posted June 28, 2019 Share Posted June 28, 2019 (edited) Assumptions Edited June 28, 2019 by Bobbie Bobster Quote Link to comment Share on other sites More sharing options...
Chinahand Posted June 28, 2019 Share Posted June 28, 2019 The answer is 4. Bobbies’ equation needs some more assumptions. ;-) Quote Link to comment Share on other sites More sharing options...
Chinahand Posted June 28, 2019 Share Posted June 28, 2019 Now Bobbie, editing away your workings leaves us in the dark!! Quote Link to comment Share on other sites More sharing options...
Chinahand Posted June 28, 2019 Share Posted June 28, 2019 I think everyone gets if the smaller circle was run along a flat surface with a length three times the circumference of the circle it would rotate three times. But this isn't what we've got in the question. Quote Link to comment Share on other sites More sharing options...
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