Hi anju_c_m,
There's a big 'take away' from Brent's example - if you EVER are unsure about how how a math rule/formula/pattern "works", then you should come up with a simple example (or two) and note the results. Math is all about patterns, and the 'rules' never change - so once you define how some simple examples work, then you can use that knowledge to define how a trickier-looking example works. In this case, we needed to define how fractions convert to percents; once that pattern is defined, answering the given question becomes a lot easier.
GMAT assassins aren't born, they're made,
Rich