Common sources of caffeine in western diet are coffee, tea, and soda drinks. Assume that 55% of western adults drink coffee, 25% drink tea and 45% drink soda. Also, assume that 15% of western adults drink both coffee and tea, 5% drink all three beverages, 25% drink both coffee as well as soda and 5% drink only tea.
1. Determine the probability that a randomly selected adult drinks only soda?
2. Determine the probability that a randomly selected adult drinks none of these three beverages?