Owen bred 21 turtles, and Johanna has 5 fewer turtles than Owen. After 1 month, Owen has twice as many turtles as before and Johanna loses half of her turtles and donates the rest to Owen. How many turtles did Owen have?
Johanna had 21 turtles - 5 turtles = <<21-5=16>>16 turtles.
After 1 month, Owen was left with 21 turtles * 2 = <<21*2=42>>42 turtles.
After 1 month, Johanna was left with 16 turtles / 2 = <<16/2=8>>8 turtles.
After Johanna's donation, Owen was left with 42 turtles + 8 turtles = <<42+8=50>>50 turtles.
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