Question

The Centers for Disease Control and Prevention receives information about the causes for HIV/AIDS infection in the United States. Here are the causes of infection and their respective probability among American women ages 20 to 24 years old.

Cause	Probability
Injection drug use	?
Heterosexual sex	0.664
Perinatal infection	0.125
Other causes	0.095

Assuming this is a legitimate probability model, What is the probability that an American woman age 20 to 24 was infected via injection drug use?  

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What is the probability that an American woman age 20 to 24 contracted HIV/AIDS either via heterosexual sex or via perinatal infection?     

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What is the probability that an American woman age 20 to 24 contracted HIV/AIDS neither via heterosexual sex nor via perinatal infection?   

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Answer 1