prompt: Karina was born in 1970 and she is currently twice as old as her brother. If her current age is 40, in what year was her brother born?
messages.content: Karina was born in 1970 and she is currently twice as old as her brother. If her current age is 40, in what year was her brother born?
messages.role: user
messages.content: If Karina is currently 40, and she is twice as old as her brother, then her brother is currently 40/2 = <<40/2=20>>20 years old.
  If Karina was born in 1970, then her brother was born in 1970+20 = <<1970+20=1990>>1990
  #### 1990
messages.role: assistant