Era sells communication equipment for the civilian and military sectors. Most of its sales are in the military sector and concern interception radars. Era makes a profit of $250 per interceptor radar sold. Annual sales of these radars depend on market conditions and are estimated using the following probability distribution:

X (number of radars sold per year) f(x) (probability) 1000 0,1 3000 0,3 5000 0.4 10000 0,2