Most of the test questions are moderately challenging, helping to make the testing session more interesting and less stressful. Because an adaptive test tailors itself to your ability, it is possible that someone who is less proficient than you would answer the same number of questions correctly that you did. Therefore, counting the number of correct answers is not a good way to score an adaptive test. Adaptive test scores are based on the difficulty of the questions you answer correctly and incorrectly not on the number of questions answered correctly. In other words, the score is based on the difficulty levels of the questions you can answer correctly, rather than simply on the number of questions you answered correctly.
All tests have a similar passing rate.
From that perspective one test is no harder than any other is. However, it takes a great deal of preparation, even over-preparation, to pass them. If you do not pass an exam the first time, you may retake it at any time. If you do not achieve a passing score a second time, you must wait at least 14 days to retake the exam a third time. A 14-day waiting period will be imposed for all subsequent exam retakes.