A person moving through a tuberculosis prone zone has a 50% probability of becoming infected. However, only 30% of infec...

Question

A person moving through a tuberculosis prone zone has a 50% probability of becoming infected. However, only 30% of infected people develop the disease. What percentage of people moving through a tuberculosis prone zone remains infected but does not show symptoms of disease?

A. 15
B. 33
C. 35
D. 37

Accepted Answer

35% of people moving through the tuberculosis prone zone remain infected but do not show symptoms of disease. Answer: C. There are two sequential stages here: first, a person may or may not get infected, and second, an infected person may or may not develop symptoms. We want the fraction who are infected AND do not show symptoms. Of everyone entering the zone, 50% become infected; of those infected, 70% do not develop symptoms. Combining gives the final percentage.

A person moving through a tuberculosis prone zone has a 50% probability of becoming infected. However, only 30% of infected people develop the disease. What percentage of people moving through a tuberculosis prone zone remains infected but does not show symptoms of disease? A. 15 B. 33 C. 35 D. 37