Stacey and Jason received their scores on three tests. On the first test, Stacey's score was 10 points higher than Jason score. On the second test, Stacey's score was 4 points higher that Jason's score. if Jason's averages score on 3 tests was 3 points higher than Stacey's average score on the 3 tes...

no you won't be able to walk in and take gmat. You must register at mba.com and schedule an appointment and pay $250. usually time and date are flexible.

I took GMAT twice and i register a weak prior to that and i was able to get my time and date.