Betty's daughter is 40/100 * 60 = <<40/100*60=24>>24 years younger than she is.

That means her daughter is 60 - 24 = <<60-24=36>>36 years old.

So the granddaughter is 1/3 * 36 = <<1/3*36=12>>12 years old.

# Answer

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Question:
Betty is 60 years old, and she is the oldest person in the family. Her daughter is 40 percent younger than she is, and her granddaughter is one-third her mother's age. How old is the granddaughter?
Answer:
Let's think step by step.

user
12
Betty is 60 years old, and she is the oldest person in the family. Her daughter is 40 percent younger than she is, and her granddaughter is one-third her mother's age. How old is the granddaughter?
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