There are a total of 3 blocks of candy * 30 pieces of candy per candy block = <<3*30=90>>90 pieces of candy.
Using this, Jan can create 90 pieces of candy / 10 pieces of candy per candy necklace = <<90/10=9>>9 candy necklaces.
As Jan is keeping a candy necklace too, there must have been enough candy necklaces for 9 candy necklaces – 1 candy necklace for Jan = <<9-1=8>>8 friends.
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