Rolling coins

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You have two coins of the same size and roll one around the other.
How many times does the rolling coin roll around its center?

Hint: It’s not one!

What if the coins were different sizes?

9 thoughts on “Rolling coins”

  1. it’s 2 revolutions…..for diff size the ans will be r1/r2+1…..where r1 and r2 are radius of static and rotating circles respectively.

  2. umm 2 i gess i am dumb lol 🙂 LOL ON ME HAHAHAHAHAHAAHAHAHHAHAHHAHAHAHAHAHHAHAHAHAHAHAHAHAHHahahahahahahahhahshhhhahahahahahahahahahahahahahahah

  3. This is pretty easy. Answer is 1.5

    Because when the outer coin roles, it makes a bigger circle outside with diameter of 2*r1+r2 or 3*r1 if they are equal size. The circumference of bigger circle will be 2*pi*(3*r1/2) and for outer coin we have 2*pi*r1 . If we divide these two we get the answer which is 1.5

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