My first (favorite) approach is the same as mclchu's.

However, I do have a second approach:

Let's use the technique of performing the same operation on each quantity. By the way, I have a free video on this strategy here:

http://www.greenlighttestprep.com/module/gre-quantitative-comparison?id=1097Quantity A: (2^30 - 2^29)/2

Quantity B: 2^28

Multiply both quantities by

2 to get:

Quantity A: 2^30 - 2^29

Quantity B: (2^28)(

2^1) = 2^29

Add 2^29 to both quantities to get:

Quantity A: 2^30

Quantity B: 2^29 + 2^29

NOTE: adding the same quantity to itself is the same a multiplying that quantity by 2. For example, 7 + 7 = 2(7) and 11 + 11 = 2(11)

So, 2^29 + 2^29 = 2(2^29)

So, we get:

Quantity A: 2^30

Quantity B: 2(2^29) = (2^1)(2^29) = 2^30

Answer:

Cheers,

Brent

_________________

Brent Hanneson – Creator of greenlighttestprep.com

If you enjoy my solutions, you'll like my GRE prep course.

Sign up for GRE Question of the Day emails