## GMAT : Graduate Management Admission Test. GMAT Data Sufficiency. Solving problems in mathematics for GMAT test-taking

### Directions: Each of the following GMAT sample data sufficiency problems contains a question followed by two statements, numbered (A) and (B).

#### You need not solve the GMAT sample data sufficiency problem; rather you must decide whether the information given is sufficient to solve the problem.

The range of mathematical topics tested on the GMAT math section
(both problem solving and data sufficiency questions) is limited to high school mathematics.
The GMAT does not test you on trigonometry or calculus.

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1.

Profit = Income – Costs, so we need to know income and costs.

Neither proposition by itself will allow us to compute the 1981 costs and income.

The information in (1) and (2) together gives us only percentage increases.

Without the actual 1980 income and cost numbers, we cannot calculate 1981 income and costs.

If the percentage increases for costs and income had been the same,
then you could have computed the new profit.
For example, if both costs and income had increased by 50 percent,
then the profit would also have increased by 50 percent.

With the given information, it is not enough.

For example, if in 1980 income were \$1,000,000 and the costs were \$400,000
(for a 1980 profit of \$600,000),
the 1981 income would be \$1,200,000 and the 1981 costs would be \$500,000,
for a 1981 profit of \$700,000.
If the 1980 figures were \$10,000,000 – \$9,400,000 = \$600,000,
then 1981 would be \$12,000,000 – \$11,750,000 = \$250,000.

This shows that you don't even know whether the profit is larger or smaller in 1981.

2.

(1) tells us that x must be positive or zero, since the cube of any negative number is negative.

From (2) we know that x is negative or odd, but not both.

Thus, given (1) and (2), x must be odd.

3.

In order to find the average speed for the whole trip,
we will at least need to have information about all of the miles of the trip.
Traveling at 50 miles per hour for the first three hours and 45 miles per hour for the last three hours, the car will have gone (50 × 3).

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GMAT Data Sufficiency Questions & Answers - Math

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Алексей Учительский,
Oct 26, 2012, 7:46 AM
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Алексей Учительский,
Oct 26, 2012, 8:27 AM