GMAT problem - Give me the quick and fast way?

Question

2 + 2+ 2^2 + 2^3 + 2^4 + 2^5 + 2^5 + 2^6 + 2^7 +2^8 + 2^9

Answer 1

2+2 = 2^2
2^2 + 2^2 = 2(2^2) = 2^3
2^3 + 2^3..... etc.

Answer 2

Shouldn't the first term be 1= 2^0?

The fast way to compute the sum of a geometric progression:

sum i=1 to n r^i = (r^(n+1) - 1) / (r-1)

In this case, n=9 and r=2 (assuming the first term was meant to be 1; otherwise, just add 1 to what the formula gives you)