Probability Theory, Exercise, Solutions, Mathematics.
P(Disease) + P(Positive | No Disease) × P(No Disease)]. Plugging in the numbers, we get [0.95 × 0.01] / [0.95 × 0.01 + 0.05 × 0.99] ≈ 0.16, or approximately 16%. 3. Let P(Red1) = 3/5 be the probability of drawing a red ball first, and P(Blue1) = 2/5 be the probability of drawing a blue ball first.