Page 238 - MATHEMATICS COURSE FOR SECONDARY SCHOOLS BOOK 2

EXAMPLE 13
U
A
B
27
C 15
32
28
NUMBER OF ELEMENTS IN THREE SETS
EXAMPLE 12
The Venn diagram shows the number of students in Form 3 who ate ackee (A), breadfruit (B) and calloloo (C).
(a) State the number of students in Form 3 who ate:
(i) ackee
(ii) both ackee and breadfruit
(iii) only callaloo
(iv) none of the three dishes
(b) How many students are there in Form 3?
(a) (i) The number of students who ate ackee n (A) = 27 + 18 + 15 = 60
(ii) The number of students who ate both ackee and the breadfruit,
n (AnB) = n (B) = 21
(iii) The number of students who ate only callaloo (C n A) = 32
(iv) The number of students who ate
more of the three dishes, n (AVC)1 = 28
(b) The number of students in Form 3, n(V) = 2n + 18 + 15 + 32 + 28 = 120
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