This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Social & Preventive Medicine
If the probability of full recovery following polio is 0.3 and the probability of paial recovery is 0.4, then the total probability of full or paial recovery following polio is: 
Select and explain. 
A. 0.12, B. 0.7, C. 1.2, D. 0.1
B: 0.7
Answer: B: 0.7 
Explanation: In case of mutually exclusive events, for example total and paial recovery, the total probability can be calculated by applying the law of addition. i.e. P (full or paial recovery)= P(full recovery)+ P(paial recovery) = 0.4+0.3=0.7 Ref: Medical biostatistics, 1st edition pg: 191