This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Epidemiology, Subject name: Social & Preventive Medicine
Relationship between incidence and prevalence - 
Select and explain. 
A. Incidence = Prevalence x Duration, B. Prevalence = Incidence x Duration, C. Incidence = Prevalence + Duration, D. Prevalence = Incidence + Duration
B: Prevalence = Incidence x Duration
Answer: B: Prevalence = Incidence x Duration 
Explanation: Ans. is 'b' i.e., Prevalence = Incidence duration * Prevalence depends upon 2 factorsi) Incidenceii) Duration of illnessPrevalence - Incidence x mean duration.