MCQ
If $19^{th}$ terms of non -zero $A.P.$ is zero, then its ($49^{th}$ term) : ($29^{th}$ term) is
  • A
    $4 : 1$ 
  • B
    $1 : 3$ 
  • $3 : 1$ 
  • D
    $2 : 1$ 

Answer

Correct option: C.
$3 : 1$ 
c
$a + 18d = 0 \Rightarrow a =  - 18d$

$\frac{{{t_{49}}}}{{{t_{29}}}} = \frac{{a + 48d}}{{a + 28d}} = \frac{{ - 18d + 48d}}{{ - 18d + 28d}}$

$ = \frac{{30d}}{{10d}} = 3$

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