conversations.from: human
conversations.value: Adrian's age is three times the age of Harriet, and Harriet is half the age of Zack. Calculate the average age of the three in three years if Harriet is 21 years old now.
  Find the solution.
conversations.from: assistant
conversations.value: In three years, Harriet will be 21+3 = 24 years old.
  Since Adrian's age is three times that of Harriet, Adrian is 3*21 = 63 years old.
  In three years, he will be 63+3 =66 years old.
  If Harriet is half times the age of Zack, Zack is 21*2 = 42 years old.
  In three years, he will be 42+3 = 45 years old.
  The combined age of the three in 3 years will be 45+66+24 = 135 years.
  The average age for the in three years will be 135/3 =45 years