In four years, Peter will be twice as old as Harriet. If Peter's age is currently half of his mother's age, who is 60, how old is Harriet now?
If Peter's age is currently half of his mother's age, who is 60, Peter is 1/2*60 = <<30=30>>30 years old.
In four years, Peter will be 30+4 = <<30+4=34>>34 years old.
Since Peter's age in four years will be twice Harriet's age, Harriet will be 34/2 = <<34/2=17>>17 years old in four years.
Currently, Harriet is 17-4 = <<17-4=13>>13 years old.
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