Answers

2014-09-13T15:26:49+05:30
Let n(A) = no. of students pass in english
    n(B) = no. of students pass in math
    n(AunionB) = no. of students pass in either math or english
    n(AintersectionB) = no.of students pass in both math and english
let x are no. of students
n(AunionB) = n(A) + n(B) - n(AintersectionB)
                 = 80x/100 + 85x/100 - 75x/100
                 = 90x/100
no. of students fail in both either math or english = x - n(AunionB)
                                                                   40 = x - 90x/100
                                                                   40 =  x/10
                                                                   x = 400
total no. of students = 400 
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