. In an examination, 80% of the students passed in English, 85% in Mathematics and 75% in both English and Mathematics. If 40% students failed in both the subject, find the total number of students.
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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
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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