2 + 22 + 23 + … + 29 = ?

Question:
2 + 22 + 23 + … + 29 = ?

[A].

2044

[B].

1022

[C].

1056

[D].

None of these

Answer: Option B

Explanation:

This is a G.P. in which a = 2, r =	22	= 2 and n = 9.
	2

Sn =	a(rn – 1)	=	2 x (29 – 1)	= 2 x (512 – 1)   = 2 x 511   = 1022.
	(r – 1)		(2 – 1)