JEE Mains · Maths · STD 11 - 8. sequence and series
If \(19^{th}\) terms of non -zero \(A.P.\) is zero, then its (\(49^{th}\) term) : (\(29^{th}\) term) is
- A \(4 : 1\)
- B \(1 : 3\)
- C \(3 : 1\)
- D \(2 : 1\)
Answer & Solution
Correct Answer
(C) \(3 : 1\)
Step-by-step Solution
Detailed explanation
\(a + 18d = 0 \Rightarrow a = - 18d\) \(\frac{{{t_{49}}}}{{{t_{29}}}} = \frac{{a + 48d}}{{a + 28d}} = \frac{{ - 18d + 48d}}{{ - 18d + 28d}}\) \( = \frac{{30d}}{{10d}} = 3\)
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