(Q26).For what value of n, are the nth terms of two APs: 63, 65, 67, ….. and 3, 10, 17,… equal?

Given : The first A.P. is 63, 65, 67, ……

where a = , d = a2 – a1,

⇒ d = =

and the second A.P. is 3, 10, 17, …….

where a = ; d = a2 – a1 = =

Suppose the nth terms of the two A.Ps are equal, where an = a + (n – 1)d

+ (n – 1) = + (n – 1)

+ n – = + n –

+ n = n –

n – n = +

n =

⇒ n =
=

th terms of the two A.Ps are equal.