UP Police Constable Exam Model Paper 3

Given:
AP Series 25, 28, 31, 34, __________
Formula used:
${\mathrm{T}}_{\mathrm{n}}=\mathrm{a}+\left(\mathrm{n}+1\right)\mathrm{d}$
Where, a = first term and d = common difference
Calculation:
${\mathrm{T}}_{\mathrm{n}}=\mathrm{a}+\left(\mathrm{n}+1\right)\mathrm{d}$
⇒ 142 = 25 + (n – 1) × 3
⇒ 142 – 25 = (n – 1)× 3
⇒ 117 = (n – 1)× 3
⇒ (n – 1) = 39
⇒ n = 40
∴ 40${}^{\mathrm{th}}$ term is equal to 142.