ABC is a triangle. BC is perpendicular to CD. |AD|=|DB|=6 units.

|CA|=x units. What is the sum of the biggest and smallest values that x can assume?

I drew paralel AK to DC. |DC|=a and |BC|=s |AK|=2a and |CK|=s

let s=5.9 and a=0.8. Then smallest value of x is 6.

But if we sum 5.9+6 =11.9. Then biggest integer value for x is 11. Then the answer must be 17. But the book says 18.