91Ó°ÊÓ

To understand how to calculate an average score, let's look at what an average represents: the sum of all values divided by the total number of values. For example, if you want to calculate the average score of a class of students, you would add up all the individual scores and then divide by the number of students.

Mathematically, if you have scores of different groups, you need to know the individual scores for each group to find the overall average. If you only have the average scores for each group, you must also know the number of students in each group.

To break it down for our problem: if the average scores for groups 1 to 5 are known but not for 6 to 10, we can't calculate the overall average without those additional groups. The same applies if only groups 6 to 10 are known without groups 1 to 5. Thus, knowing the averages for all individual groups is essential for calculating the total average score for the 200 students.

Data sufficiency questions are a critical part of the GMAT exam. They test your ability to determine whether the information given is enough to solve a problem, rather than actually solving it.

For data sufficiency questions, you often need to analyze each statement alone before combining them. Here's a step-by-step guide for such problems:

• First, understand the question and determine what specific information is required to answer it.
• Second, analyze each statement independently. Ask yourself, 'Is this statement alone enough to provide the required information?'
• Third, combine the statements to see if together they provide sufficient information to answer the question.

In our example, neither Statement (1) nor (2) alone provides enough information to calculate the overall average score. However, when combined, they give the average scores for all 10 groups, making it possible to find the overall average score for all students.

Preparing for the GMAT involves understanding different types of questions, including problem-solving and data sufficiency. Successful test preparation requires strong mathematical, analytical, and critical thinking skills.

Here are essential tips for GMAT preparation:

• Focus on understanding fundamental mathematical concepts, including arithmetic, algebra, and geometry.
• Practice data sufficiency questions regularly to get familiar with the format and develop a strategy for quick analysis.
• Develop a study schedule to cover all sections of the GMAT, including quantitative, verbal, and integrated reasoning.
• Take timed practice tests to improve time management and reduce exam-day anxiety.
• Review your answers, especially the incorrect ones, to understand where you went wrong and how you can improve.

By breaking down the study plan into manageable sections and practicing consistently, you can enhance your skills and increase your confidence for the exam day.