Question

Find the eighteenth term of the A. P. : 1, 7, 13, 19, ...

Answer 1

In the given A.P., we have:
a = 1 and d = t₂ – t₁ = 7 – 1 = 6
We know that the n^th term of an A.P. is t_n = a + (n – 1)d.
To find the 18^th term of the given A.P., we need to take n = 18.
Thus, we have:
t₁₈ = 1 + (18 – 1)6
= 1 + 17 × 6
= 1 + 102
= 103
Therefore, the 18^th term of the given A.P. is 103.