adding multiple expoonents

[recko2430]

What is the fastest way of doing this question?

2+2+2^2+2^3+2^4+2^5+2^6+2^7+2^8

A) 2^9
B) 2^10
C) 2^16
D) 2^35
E) 2^37

[sudhir3127]

What is the fastest way of doing this question?

2+2+2^2+2^3+2^4+2^5+2^6+2^7+2^8

A) 2^9
B) 2^10
C) 2^16
D) 2^35
E) 2^37

its 2^9
if u read the question carefully u will realise.
2+2+2^2+2^3+2^4+2^5+2^6+2^7+2^8 can also be written as

2^2+2^2+2^3..............

we know that 2^n+ 2^n = 2^n+1.........
therefore the whole equation will add upto
2^8+1 = 2^9

do let me know if u have any doubts..

[jnellaz]

https://www.beatthegmat.com/roots-t22564.html