Question

5. The data represent scores of 9 applicants in an interview arranged in ascending order:
(3x+2), 22, (4x−2), 23, 25, (5x−4), 29, 29 and (x²−7).
(a) Given that the range is 9, find:
   (i) value of x
   (ii) mean mark of the applicants.
(b) If four of the applicants who obtained the highest score were selected, determine the pass mark.

Accepted Answer

(a)(i) Range = Highest − Lowest = 9
   (x²−7) − (3x+2) = 9
   x²−3x−9 = 9 → x²−3x−18 = 0
   (x+3)(x−6) = 0 → x = 6
(a)(ii) Mean = (20+22+22+23+25+26+29+29+29)/9
   Substituting x=6 → mean = 25
(b) Pass mark = 26 (4th highest score)

WAEC Mathematics 2025 Theory — Question 5

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