Two insured persons, Mr. Andreas and Mrs. Vassiliki, have concluded the same health insurance contract for the costs of hospital treatment, according to which the insurance company is exempt for the first 1500 Euros, the percentage of the insured's participation in the costs of hospitalization is 50%, and the maximum payment amount of the insured is 5000 Euros.
a) What is the maximum amount of participation of Mr. Andreas and Mrs. Vasiliki in the hospital expenses?
b) What amount does the company cover for each insured, if the total hospitalization costs of Mr. Andreas are 12000 and Mrs. Vasiliki's are 8000?