IBPS Clerk Prelims Model Paper 15

Let a be the first term and n number of term th and d common difference then,
an = a + (n — 1) d
⇒ a3 = a + (3 — 1) d
17 = a + 2d ...(i)
a17 = a + (17 — 1) d
— 25 = a + 16 d ....(ii)
Solving equations (i) and (ii)
a = 23, and d = — 3
— 1 = 23 + (n — 1) (— 3)
— 1 = 23 — 3n + 3
3n = 23 + 1 + 3
3n = 27
n = 9
— 1 is the 9th term.