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Thread: Venn's diagram (either)

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    Venn's diagram (either)

    Venn's diagram (either)-692.png

    In a school . 35 students like reading , 50 student like jogging , and 15 students like both . How many person like either reading or sports ?

    The ans is 35+ 50 -15 = 70 ( Ans given)

    but , i think the ans should be 20+ 35 = 55 only

    Which is correct ? If my ans is wrong , in what circumstances , the ans would be 20+ 35 = 55 ??
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    Re: Venn's diagram (either)

    In a school . 35 students like reading , 50 student like jogging , and 15 students like both . How many person like either reading or sports ?
    $J = 50$, $R=35$

    $J \cap R = 15$

    $J \cup R = 70$
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    Re: Venn's diagram (either)

    Quote Originally Posted by xl5899 View Post
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    In a school . 35 students like reading , 50 student like jogging , and 15 students like both . How many person like either reading or sports ?

    The ans is 35+ 50 -15 = 70 ( Ans given)

    but , i think the ans should be 20+ 35 = 55 only

    Which is correct ? If my ans is wrong , in what circumstances , the ans would be 20+ 35 = 55 ??
    There are 20 people who like only reading and not jogging. There are 15 people who like both reading and jogging. There are 35 people who like only jogging but not reading. How many people like either reading or jogging? That is 20+15+35 = 70.
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    Re: Venn's diagram (either)

    Quote Originally Posted by SlipEternal View Post
    There are 20 people who like only reading and not jogging. There are 15 people who like both reading and jogging. There are 35 people who like only jogging but not reading. How many people like either reading or jogging? That is 20+15+35 = 70.
    why we have to inclide the people like both jogging and reading ?
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    Re: Venn's diagram (either)

    Quote Originally Posted by xl5899 View Post
    why we have to inclide the people like both jogging and reading ?
    Why not? You need to tell us why you think not.

    $\|J\|$ is the number of whatever having property $J$.

    $\|J\cup R\|=\|J\|+\|R\|-\|J\cap R\|$
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