Question

6(a). In a class of 80 students, 3/4 study Biology and 3/5 study Physics. If each student studies at least one of the subjects: (i) draw a Venn diagram to represent this information; (ii) how many students study both subjects; (iii) find the fraction of the class that study Biology but not Physics.

Accepted Answer

n(Biology) = 3/4×80 = 60. n(Physics) = 3/5×80 = 48. n(U)=80. Both = n(B)+n(P)−n(U) = 60+48−80 = 28. (i) Venn diagram: two overlapping circles B and P inside a universal set of 80, with 28 in the overlap, 32 in B only, 20 in P only. (ii) 28 students study both. (iii) Biology only = 60−28 = 32; fraction = 32/80 = 2/5.

WAEC Mathematics 2021 Theory — Question 8

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