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Nice Easy Puzzle For Ya ............
25 Answers
In the figure below, the radius of circle A is 2 units, the radius of circle B is 3 units.
Starting from the position shown in the figure, circle A rolls around circle B (circle B remains stationary).
At the end of how many revolutions of circle A, will the centre of circle A be back at its starting point ??
Link to image:
http:// i264.ph otobuck et.com/ albums/ ii200/B urnleym oonbeam /circle s2_zpsa 7f10d41 .gif
Starting from the position shown in the figure, circle A rolls around circle B (circle B remains stationary).
At the end of how many revolutions of circle A, will the centre of circle A be back at its starting point ??
Link to image:
http://
Answers
Ah -- changes the way I was looking at the question, which was in trying to get the lines aligned again (I think then 3 is still wrong, of course, by grasscarps' logic). So 1.5 + 1 = 2.5?
16:20 Fri 31st Oct 2014
Jim just beat you to it :(
Just to fully explain the answer:
If you take the circumference of circle B and flatten it out into a straight line and let circle A roll over it, circle A will make 1.5 revolutions to cross it. However, when it rotates around circle B, it's also rotating around its axis and therefore makes 1 more revolution, so the answer is 2.5 and not 1.5 as most people think.
Just to fully explain the answer:
If you take the circumference of circle B and flatten it out into a straight line and let circle A roll over it, circle A will make 1.5 revolutions to cross it. However, when it rotates around circle B, it's also rotating around its axis and therefore makes 1 more revolution, so the answer is 2.5 and not 1.5 as most people think.