The first term of an Arithmetic Progression is 22 and the

The first term of an Arithmetic Progression is 22 and the last term is – 11. If the sum is 66, the number of terms in the sequenceis

Let Number of terms = n
First term (a) = 22
Last term (L) = –11
Sum (S) = 66

∴ S =	n	(a + L)
	2

⇒ 66 =	n	(22 - 11)
	2

⇒ 66 =	11n
	2

⇒ 11n = 66 × 2

⇒ n =	66 × 2	= 12
	11