Statistics And Probability Question 346
Question: The chances to fail in Physics are 20% and the chances to fail in Mathematics are 10%. What are the chances to fail in at least one subject
Options:
A) 28%
B) 38%
C) 72%
D) 82%
Show Answer
Answer:
Correct Answer: A
Solution:
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Let $ P(A)=\frac{20}{100}=\frac{1}{5}, $ $ P(B)=\frac{10}{100}=\frac{1}{10} $ Since events are independent and we have to find $ P(A\cup B)=P(A)+P(B)-P(A)\,.\,P(B) $ $ =\frac{1}{5}+\frac{1}{10}-\frac{1}{5}\times \frac{1}{10}=\frac{3}{10}-\frac{1}{50}=\frac{14}{50}=\frac{14}{50}\times 100=28%. $
BETA
