Arithmetic Progression

Which term of the A.P $\;$ $5, \; 12, \; 19, \; 26, \; 33, \; \cdots$ $\;$ will be $35$ more than its $12^{th}$ term?


Given A.P : $\;$ $5, \; 12, \; 19, \; 26, \; 33, \; \cdots$

First term of A.P $= a = 5$

Common difference of A.P $= d = 7$

Let $n^{th}$ term of A.P be $35$ more than its $12^{th}$ term.

$n^{th}$ term of A.P $= t_n = a + \left(n - 1\right)d = 5 + \left(n - 1\right) \times 7$

$12^{th}$ term of A.P $= t_{12} = 5 + \left(12 - 1\right) \times 7 = 82$

As per question,

$5 + \left(n - 1\right) \times 7 = 82 + 35$

i.e. $\;$ $5 + 7n - 7 = 117$

i.e. $\;$ $7n = 105$ $\implies$ $n = 15$

$\therefore \;$ The $15^{th}$ term of the given A.P will be $35$ more than its $12^{th}$ term.