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 =
∴ th terms of the two A.Ps are equal.