Coke machine

The coke machine in college takes 50 pence pieces. It also takes a certain foreign coin of traditional design...
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Problem



The coke machine in college takes 50 pence pieces. It also takes a certain (circular) foreign coin of traditional design.

Coins inserted into the machine slide down a chute into the machine and a drink is duly released.

How many more revolutions does the foreign coin make over the 50 pence piece going down the chute?