New method for detecting anthrax. Researchers at the University of South Florida Center for Biological Defense have developed a safe method for rapidly detecting anthrax spores in powders and on surfaces (USF Magazine, Summer 2002). Consider a powder specimen that has exactly 10 anthrax spores. Suppose that the number of anthrax spores in the sample detected by the new method follows an approximate uniform distribution between 10 and 20.

a. Find the probability that 16 or fewer anthrax spores are detected in the powder specimen

b. Find the probability that between 12 and 15 anthrax spores are detected in the powder specimen.