JAMB Mathematics 2021 Objective — Question 2
Question 2 of 40 from the Joint Admissions and Matriculation Board (JAMB) Mathematics 2021 Objective paper, with the correct answer and a full explanation.
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An A.P has 14 as its second term and 38 as its fifth term. Its tenth term and the sum of its first five terms are respectively
- A. 75,110
- B. 65,124
- C. 110,78Correct
- D. 141,33
Explanation
Tn = a + (n-1)d. T2 = a+d = 14, T5 = a+4d = 38. Subtracting: 3d = 24, d = 8, a = 6. T10 = a+9d = 6+72 = 78. S5 = 5/2[2(6)+4(8)] = 5/2(44) = 110. So the tenth term (78) and sum of first five terms (110) match option (c).
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