WAEC Mathematics 2014 Theory — Question 4

Question 4 of 23 from the West African Examinations Council (WAEC) Mathematics 2014 Theory paper, with the correct answer and a full explanation.

2(b). If 124ₙ = 232₅, find n.

Model answer

232₅ in base 10 = 2×25 + 3×5 + 2 = 50+15+2 = 67 124ₙ = n²+2n+4 = 67 n²+2n−63=0 (n+9)(n−7)=0 n=7 (taking the positive root)

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