Question 1168149
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From the condition,

    P(English OR Math) = 100% - 69% = 31%.



From the basic formula of the Elementary Probability theory

    P(English OR Math) = P(English) + P(Math) - P(English AND Math).



Substitute all known / given values into this formula

    31% = 21% + 28% - P(English AND Math).



From this equation, find P(English AND Math)

    P(English AND Math) = 21% + 28% - 31% = 18%.    <U>ANSWER</U>
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Solved.