ECZ 2013 · O-Level Paper 2 · Question 4 — Sets

Question from ECZ 2013 · O-Level Paper 2 · Question 4

(a) The diagram below shows three sets A, B and C. Given that n(A ∪ B ∪ C) = 50, find

(a(i)) the value of x,[2]

Verified working — step 1

The three sets together hold 50 members.

(a(ii)) n(A ∪ B),[1]

Verified working — step 1

A union B holds A only, A intersect B, B only and B intersect C.

(a(iii)) n(B ∪ C)',[1]

Verified working — step 1

B union C holds 8 + 3 + 24 + 5 = 40 members.

(a(iv)) n(A' ∩ C').[2]

Verified working — step 1

A' intersect C' holds everything outside BOTH A and C.

(b) Solve -5x - 9 ≤ 16.[2]

Verified working — step 1

-5x - 9 ≤ 16

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Original examination question © Examinations Council of Zambia. Worked solution and commentary © G12 Titan — not to be reproduced without permission.

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