Avoid unnecessary calculations

Last updated: 3 Mar 2007

You are so used to working out the answer in math questions and that when you first start data sufficiency questions it is easy to find yourself doing unnecessary calculations to work out the answers from the data you are given.

In fact if you find yourself doing lots of calculations on a data sufficiency question then you are almost certainly approaching it in the wrong way.

For example

What is the area of rectangle ABCD?

  1. AB is 6.125cm long
  2. BC is 12.375 cm long
  1. Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient
  2. Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient
  3. BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient
  4. EACH statement ALONE is sufficient
  5. Statements (1) and (2) TOGETHER are NOT sufficient

It should be obvious to you that you need both the length and width of the rectangle to find the area and therefore that the answer is C.

However you do not have to multiply 6.125 x 12.375 to work out the area.

Early on you will be tempted to do the calculations to find the answer in data sufficiency because you will lack confidence in your answers.

This is a habit that you must break as soon as possible.

You should aim to spend significantly less time on data sufficiency questions than you do on problem solving questions because you rarely have to do any calculations.

Once you are well practiced it should take you on average about 1.5 minutes per data sufficiency question which will leave you nearer 2.5 minutes per problem solving question.

Those extra seconds on the problem solving questions are invaluable if you are to score well in the quantitative section of the GMAT.

Next page: Process of elimination

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