human
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?
assistant
How old is Karina's brother? ** 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.
How old was Karina's brother when he was born? ** If Karina was born in 1970, then her brother was born in 1970+20 = <<1970+20=1990>>1990
#### 1990