Answer:
21
Step-by-step explanation:
We can set Andrea's current age as x.
In 11 years, her age will be half the square of her age 13 years ago. We get the equation:
[tex]x+11=\frac{(x-13)^2}{2} \\2(x+11)=(x-13)^2\\2x+22=x^2-26x+169\\x^2-28x+147=0\\(x-21)(x-7)=0\\x=21, x=7[/tex]
Ok, now we know that Andreas age could be either 21 or 7. However, the problem states that "in 11 more years my age will be hald the square of my age 13 years ago." It would not make sense for Andrea to be currently 7 if she was not yet born 13 years ago.
Therefore, Andrea's age is 21.
I hope this helps! Let me know if you have any questions :)
