Further MathematicsSequences and seriesWAEC
Which term of the arithmetic progression 5, 9, 13, ... is 81?
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Answer: A. the 20th
5 + 4(n − 1) = 81 gives n − 1 = 19, so n = 20.
An AdmitMe practice question, written for the WAEC syllabus. Not an official past question.