WAEC Mathematics 2017 Objective — Question 4

Question 4 of 50 from the West African Examinations Council (WAEC) Mathematics 2017 Objective paper, with the correct answer and a full explanation.

Fig. 1 and Fig. 2 are the addition and multiplication tables respectively in modulo 5. Use these tables to solve the equation (n⊗4)⊕3 = 0(mod 5)

• A. A. 1
• B. B. 2
• C. C. 3Correct
• D. D. 4

Explanation

Under operation ⊗, pick 3 for n: 3x4=12(mod5)=2. Taking 2 under operation ⊕: 2+3=0(mod5)=0. Therefore n=3.

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