The demand for oxygen by the bacteria is called the biological oxygen demand (BOD). A study of streams located near an industrial complex revealed that 35% have high BOD, 10% show high acidity, and 40% of streams with high acidity have a high BOD. What is the probability that a randomly selected stream will have both characteristics? My thoughts are conditional probability to address this but not sure on this one. Solution P(both) = P(high acidity)*P(high BOD|high acidity) = 0.10*0.40 = 0.04.