COMEDK · Maths · 5. Sequences and Series
The first and fifth terms of an A.P. are -14 and 2 respectively and the sum of its \(n\) terms is 40 . The value of \(n\) is
- A 8
- B 12
- C 10
- D 13
Answer & Solution
Correct Answer
(C) 10
Step-by-step Solution
Detailed explanation
Let the first term of the arithmetic progression be \(a\) and the common difference be \(d\). Given \(a = -14\) and the fifth term \(a_5 = a + 4d = 2\). Substituting \(a = -14\) into the equation \(a + 4d = 2\): \(-14 + 4d = 2 \Rightarrow 4d = 16 \Rightarrow d = 4\). The sum of…
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