Suppose that A and B play a strange game. At the beginning of the game A can choose one real number - $x$ - between $0$ and $60$. Each round of the game goes like this:
B names random real number $b$ between $0$ and $60$ with uniform probability.
If $b > x$ then A pays $3(b - x)$ dollars. If $b <= x$ then A pays $x - b$ dollars.
How should A choose $x$ so that the expected payment is minimal?