Rick’s oldest brother is 15 years * 2 = <<15*2=30>>30 years old.
This means the middle brother is 30 years / 3 = <<30/3=10>>10 years old.
The smallest brother is therefore 10 years / 2 = <<10/2=5>>5 years old.
So the youngest brother is 5 years – 2 years = <<5-2=3>>3 years old.
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