The sum of first 45 natural numbers is:

Question:
The sum of first 45 natural numbers is:

[A].

1035

[B].

1280

[C].

2070

[D].

2140

Answer: Option A

Explanation:

Let Sn = (1 + 2 + 3 + … + 45)

This is an A.P. in which a = 1, d = 1, n = 45 and l = 45

Sn =	n	(a + l)	=	45	x (1 + 45)   = (45 x 23)   = 1035
	2			2

Required sum = 1035.