On a certain road 10% of the motorists exceed the posted speed limit

Hi Saransh123,

To start, the original poster that you're referring to has not logged into GMATClub in almost a year, so you might not receive a direct response from him/her. Most GMAT questions can be approached in more than one way, so when dealing with any individual prompt, you have 2 goals: correctly answer the question (in a reasonable amount of time, if possible) AND do your work in an efficient way (meaning that you don't want to over-commit and spend too much time on any one prompt).

From your post, it's not clear what method you used to answer this question, but if you read the other posts in the thread, you'll see that by TESTing VALUES and doing a little Algebra/Arithmetic, it's possible to answer this question relatively quickly.

GMAT assassins aren't born, they're made,
Rich