Question:
In a sample survey of 645 people, it was found that 516 people have a high school certificate. If a person is chosen at random, what is the probability that he / she has a high school certificate?
(a) $\frac{1}{2}$
(b) $\frac{3}{5}$
(c) $\frac{7}{10}$
(d) $\frac{4}{5}$
Solution:
Total number of people surveyed = 645
Number of people who have a high school certificate = 516
$\therefore P(P e r s o n$ has a high school certificate $)=\frac{\text { Number of people who have a high school certificate }}{\text { Total number of people surveyed }}=\frac{516}{645}=\frac{4}{5}$
Hence, the correct answer is option (d).