GMAT Data Sufficiency Lessons | Online Class

Welcome to the Youtube live session of Data Sufficiency. The session starts with the basic lessons of GMAT DS, data sufficiency answer options, and tips and method to solve a typical DS question. The questions discussed on July 1, 2017 during the live session follow the embedded video. The video link next to each question will take you to the start of the part of the video where that specific question is discussed. Click the video embedded below to watch the entire session.

Watch this GMAT Data Sufficiency | Youtube Live Session

Questions discussed in this Video

Easy Questions

What is n?
1. n > 10
2. n < 12
Choice E
Key Point while solving this Number Properties DS Question

Do not make unwarranted assumptions about what kind of a number is 'n'? If nothing is mentioned, the only possibility is that 'n' can be any real number.
Is x = 3?
1. x² = 9
2. x < 0
Choice B
Approach to solve this GMAT Numbers DS Question

Data is sufficiency if you get a conclusive answer? Note, in this question, we have to determine whether x equals 3. We need not find a value for x. There is a significant difference between the two when it comes to data sufficiency. If the statement gives a definite yes as answer, data is sufficient. If the statement gives a definite no as answer, data is sufficient.
Is x = 3?
1. x² = 16
2. x > 0
Choice A
Key Point to solve this GMAT Question

Keep in mind that getting a conclusive NO as answer will mean that the data is sufficient.
If * is one of addition, subtraction, multiplication or division what is 7 * 0?
1. 0 * 5 = 5
2. 5 * 0 = 5
Choice D
What should you watch out for when solving this GMAT DS Question?

You have to get a conclusive answer for the question asked. You may or may not get a conclusive answer for questions asked at the intermediate stage.
What is the area of triangle ABC?
1. Two sides of the triangle measure 5 and 10
2. The triangle is an isosceles triangle.
Choice C
Concept required to solve this GMAT DS Question

Sum of the two shorter sides of the triangle should be greater than the longest side of the triangle.

Medium Difficulty Questions

What is the area of triangle ABC whose perimeter is 30?
1. One of the angles measures 80°.
2. The triangle is an isosceles triangle.
Choice E
Main idea to solve this GMAT Data Sufficiency Question

Check whether the statement(s) provide you with adequate information to determine whether the triangle under consideration is unique. If you zero it down to a unique triangle, the data is sufficient. If more than one triangle is possible with the given information, the data is not sufficient.
What is the area of triangle ABC?
1. Two sides measure 6 and 8
2. One of the angles measures 90°
Choice E
What should you watch out for when solving this GMAT DS Question

It's not always Pythagorean triplets that form right triangles. Take a few moments to get clarity on which sides are perpendicular sides and which can be the hypotenuse before rushing to answer the question.
What is the value of the largest of five positive integers?
1. The average is 40 and the median is 40.
2. The median is 40 and the range is 70.
Choice E
Approach to solve this GMAT Statistics Data Sufficiency Question

Check to see whether the question is asking for the maximum possible value of the largest number or the value of the largest number before settling for an answer option.
Is x³ > x²?
1. x > 0
2. x < 1
Choice B
Approach to solve this GMAT Inequalities DS Question

The question tests your understanding of the four intervals in which different exponents of a number behave differently. The intervals to evaluate are (- ∞ -1), (-1, 0) (0, 1), and (1, ∞). Evaluate to check whether the statement(s) provide a conclusive yes or conclusive no.

Hard Questions

Is the quadrilateral ABCD a parallelogram?
1. A pair of opposite sides is parallel.
2. A pair of opposite sides is equal.
Choice E
Approach to solve this GMAT Geometry DS Question

Solving this question involves two parts. Part 1: understanding the properties of different quadrilaterals including parallelogram. Part 2: Ability to look for a counter example and back it with properties of quadrilaterals.
What is the remainder when N is divided by 14?
1. N divided by 28, the remainder is 20.
2. N divided by 7, the remainder is 6.
Choice A
Hint to solve this GMAT DS Question

It is possible to determine a unique remainder if the second divisor is a factor of the first one. However, there exist more than one remainder if the second divisor is a multiple of the first one.
If N is a positive integer, is N² divisible by 48?
1. N³ is a multiple of 24.
2. N is a multiple of 18.
Choice E
Approach to solve this GMAT Number Theory DS Question

What should N² contain if it has to be a multiple of 48. It has to be a multiple of 48 or its prime factorized equivalent, 2⁴ × 3. Evaluate the two statements to determine whether you can determine this information.
Is |a| > |b|?
1. a > b
2. (a + b) < 0
Choice C
Points to note while solve this GMAT Number Properties DS Question

Point 1: When will |a| be greater than |b| if a > b.
Point 2: What does it mean that the sum of two numbers is negative?

Very Hard Questions

Is the positive integer P prime?
1. 2^P - 1 is prime.
2. P + 4 is a perfect square.
Choice A
Approach to solve this GMAT Data Sufficiency Question

Statement 1: It requires knowing what Mersenne Primes are to conclusively determine whether statement A is sufficient. An examination alternative is to check with a few numbers that satisfy the condition in statement 1 and determine the answer to the question. Though, using a few numbers to determine sufficiency is not conclusive, in the absence of some specific knowledge, that is the best one can do.
Is the positive integer N divisible by 12?
1. 2N has lesser number of factors than 3N.
2. 3N has lesser number of factors than 5N.
Choice C
Key Point to use to solve this GMAT DS Question

If a number N does not contain a prime number P, then when the number of factors of PN will be twice the number of factors that N has. However, if N already has P as one of its prime factors, PN will have lesser than twice the number of factors that N has. How much lesser is determined by how high the power of the prime P in N. Greater the power, lower the value of the multiple.
Consider triangle ABC with AB = 6 cm. Which is the smallest side of this triangle?
1. BC = 7 cm
2. Angle ACB is 70°.
Choice C
Approach to solve this Geometry DS Question

Property Tested: Side opposite the smallest angle is the shortest side in a triangle.