Sally's age is 12 years plus half her age How old is she?

Half of 12 is 6, thus 12 years old plus half her age (6 years) = 18 years old. Unless however there is some hidden trick in logic to this. 18 is incorrect, half of 18 is 9. 9 + 12 = 21 correct answer is 24. sally's age is 12 years plus half her age. 12 + 12 = 24. half of 24 is 12