Answer:
(a) = 13
(b) = 8
(c) = 5
Step-by-step explanation:
Addition theorems on sets are
Theorem 1 :
n(AuB) = n(A) + n(B) - n(AnB)
Theorem 2 :
n(AuBuC) : = n(A) + n(B) + n(C) - n(AnB) - n(BnC) - n(AnC) + n(AnBnC)
Total number of students in the school is not given
so let there are 60 students in the school
using theorem 2
n(AuBuC) : = n(A) + n(B) + n(C) - n(AnB) - n(BnC) - n(AnC) + n(AnBnC)
let n(A) = Mathematics, n(B) =Physics and n(C) = Chemistry
so putting values,
60 = 40 + 42 + 38 - 20 - 28 - 25 + n(AnBnC)
60 +73 -120 = n(AnBnC)
13 = n(AnBnC)
therefore, there are total 13 students who take all three subjects
Number of students who had taken only Mathematics =
n(A) - n(AnB) - n(AnC) + n(AnBnC)
40 - 20 - 25 + 13
53 - 45 = 8 students
Number of students who had taken only Physics =
n(B) - n(BnA) - n(BnC) + n(AnBnC)
42 - 20 - 28 + 13
53 - 48 = 5 students
learn more about sets and vein diagrams at
brainly.com/question/2332158
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