Assume that the only possible causes of symptom a are d1 d2

Question

Diseases D₁. D₂. and D₃ cause symptom A with probabilities 0.5. 0.7, and 0.8. respectively. if 5% of a population have disease D₁, 2% have disease D₂, and 3.5% have disease D₃, what percent of the population have symptom A? Assume that the only possible causes of symptom A are D₁, D₂, and Di and that no one carries more than one of these three diseases.