Joseph gave 16 x 3/8 = <<16*3/8=6>>6 cards to his brother.
He gave a total of 6 + 2 = <<6+2=8>>8 cards to his brother and friend.
Joseph has 16 - 8 = <<16-8=8>>8 cards left.
This is 8/16 x 100% = 50% of his cards.
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