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100 Hardest Data Sufficiency Questions [#permalink]
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30 Oct 2013, 02:26
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100 Hardest Data Sufficiency Questions Are you familiar with the GMAT Club's timer? We have pulled timer results from our database and analyzed every question in the forum. Based on those results, we have compiled a list of the hardest questions in each of the question forums we have. Below I am presenting to you the top 100 questions from DS forum.
Data Sufficiency (DS)  Rank  Title  Topics  1  Train A leaves New York for Boston at 3 PM and travels at  Distance/Rate Problems  2  Bob and Wendy left home to walk together to a restaurant for  Distance/Rate Problems  3  For integers a and b, if (a^3 a^2 b)^1/2 = 7, what is the  Algebra  4  If, in the addition problem above, a, b, c, d, e, f, x, y, a  Arithmetic  6  If a does not = 0, is 1/a > a/(b^4 + 3)  Algebra/Inequalities  7  w, x, y, and z are integers. If z > y > x > w, is w > x^2  Inequalities/Absolute Values/Modules  8  w, x, y, and z are integers. If w >x>y>z>0, is y a common  Number Properties/Divisibility/Multiples/Factors  9  In a group of 80 college students, how many own a car? (1)  Overlapping Sets  10  In the correctly worked addition problem above, A, B, C, D  Arithmetic/Number Properties  11  A rectangle is plotted on the standard coordinate plane  Coordinate Geometry  12  If w>x>y>z>0, is z>4?  Fractions/Ratios/Decimals/Inequalities  13  The average of 5 distinct single digit integers is 5. If  Number Properties  15  If 20 Swiss Francs is enough to buy 9 notebooks and 3  Inequalities/Word Problems  16  Is 2a 3b < a b + a 2b  Absolute Values/Modules  17  If x and y are positive integers, what is the greatest  Divisibility/Multiples/Factors  18  What is the perimeter of PQRS ? (1) x = 30 degree  Geometry  19  If x, y, and z are positive integers such that x < y < z  Number Properties/Divisibility/Multiples/Factors  20  How many subordinates does Marcia have?  Combinations  21  At a restaurant, a group of friends ordered four main dishes  Min/Max Problems  22  A certain salesman's yearly income is determined by a base  Percent and Interest Problems/Word Problems  23  Is 1/(xy) < y  x  Algebra/Inequalities  24  Between 1980 and 1985, Pierres investment portfolio increas  Percent and Interest Problems  25  A cube is made up of equal smaller cubes. Two of the sides  Geometry  26  Of all the attendees at a dinner party, 40% were women. If  Overlapping Sets  27  If x and y are positive integers is y odd?  Number Properties/Algebra  28  If 5a=9b=15c, what is the value of a+b+c?  Algebra  29  In a certain club, every member likes red wine or white wine  Overlapping Sets  30  Jane can paint the wall in J hours, and Bill can paint the  Work/Rate Problems/Word Problems  31  A set of nonnegative integers consists of  Sequences  32  A committee of 2 people is to be formed from a group of 8  Probability  33  In the xyplane, region R consists of all the points (x, y)  Inequalities/Coordinate Geometry  34  If x is an integer, what is the value of x?  Absolute Values/Modules  35  If the graph of y = x^2 + ax + b passes through the points  Coordinate Geometry  36  If p, x, and y are positive integers, y is odd, and p = x^2  Divisibility/Multiples/Factors/Number Properties/Remainders  37  Is x^2*y^4 an integer divisible by 9 ?  Number Properties/Divisibility/Multiples/Factors  38  A person inherited few gold coins from his father. If he  Remainders/Word Problems  40  Laura sells encyclopaedias, and her monthly income has two  Word Problems/Out of Scope  Too Hard  41  If x, y, and z are integers greater than 1, and  Number Properties/Exponents/Powers  42  If n is an integer greater than 1 is 3^n2^n divisible by 35  Number Properties/Exponents/Powers/Divisibility/Multiples/Factors  43  Is x<1?  Inequalities/Absolute Values/Modules  44  Is A + B + C even?  Number Properties  45  If a, b and c are integers such that b > a, is b+c > a  Inequalities/Geometry  46  Reiko drove from point A to point B at a constant speed, and  Distance/Rate Problems  47  If x^2 = y + 5, y = z  2 and z = 2x, is x^3 + y^2 + z  Divisibility/Multiples/Factors/Algebra  48  A Farey sequence of order n is the sequence of fractions  Sequences  49  Last year, a certain company began manufacturing product X a  Word Problems  50  At Western Springs School there are 150 total students  Overlapping Sets  51  Is A positive? x^22x+A is positive for all x Ax^2+1 is  Algebra  54  If for any positive integer x, d[x] denotes its smallest odd  Divisibility/Multiples/Factors/Functions and Custom Characters  55  x is an integer and x raised to any odd integer is greater  Exponents/Powers/Algebra  56  If x^2 = y + 5 , y = z  2 and z = 2x , is x^3 + y^2 + z  Algebra/Divisibility/Multiples/Factors  58  Six shipments of machine parts were shipped from a factory  Fractions/Ratios/Decimals/Word Problems  59  Does the curve (xa)^2 + (yb)^2=16 intersect the yaxis ?  Coordinate Geometry/Geometry  60  If a and b are positive integers, what is the remainder when  Divisibility/Multiples/Factors/Number Properties/Remainders  61  If p and q are negative, is p/q > 1  Absolute Values/Modules/Inequalities  62  Is x^2 + y^2 > 100?  Exponents/Powers/Algebra  63  If vertices of a triangle have coordinates (2,2), (3,2) and  Coordinate Geometry/Absolute Values/Modules  64  If xy 0, is x > y? (1) 4x = 3y (2) y  x = x  y  Absolute Values/Modules/Inequalities  65  Is xy<0 ? (1) x^3*y^5/x*y^2 <0 (2) xy<xy  Absolute Values/Modules/Inequalities  66  If m and n are positive integers, is the remainder of  Remainders  67  A right circular cone, twice as tall as it is wide at its  Geometry  68  If the base score is between 10 and 99, the bonus is equal  Word Problems/Arithmetic  69  Which of the two values 10^(2) and 10^(3), is x more close  Arithmetic/Exponents/Powers  70  If x is positive, what is the value of x 3 2x 4 +  Inequalities/Absolute Values/Modules  71  A car dealership carries only sedans and SUVs  Word Problems/Percent and Interest Problems  72  If a, b, and c are integers such that 0 < a < b < c < 10, is  Divisibility/Multiples/Factors  73  If x < p < q < y. Is q  x < q  y?  Inequalities/Absolute Values/Modules  75  A jar contains 8 red marbles and y white marbles. If Joan  Probability  76  If x and y are negative numbers, is x<y?  Inequalities  77  If m and n are positive integers, is m^n < n^m?  Exponents/Powers/Inequalities  78  At a particular store, candy bars are normally priced at $1.  Word Problems  79  Trains A and B left stations R and S simultaneously on two s  Distance/Rate Problems  80  How many factors does the integer X have?  Absolute Values/Modules/Algebra/Exponents/Powers  81  The sum of the integers in list S is the same as the sum of  Statistics and Sets Problems  82  What does 2b equal?  Absolute Values/Modules/Algebra  83  A circle is drawn on a coordinate plane. If a line is drawn  Geometry  84  If w, x, y and z are integers such that w/x and y/z are  Number Properties  85  If x and y are nonzero integers and x + y = 32, what is  Absolute Values/Modules  86  The integers m and p are such that 2<m<p, and m is not a  Number Properties/Remainders/Divisibility/Multiples/Factors  87  If p is a positive odd integer, what is the remainder when p  Remainders  88  Sequence S consists of 24 nonzero integers. If each term in  Sequences  89  ax + by=10, ay + bx=12. which one is greater here, x or y ?  Inequalities  90  Shaina's fivedistinctdigit locker code is 5A48B. What  Divisibility/Multiples/Factors  91  Is x > y ? (1) x^(1/2)>y (2) x^3>y  Exponents/Powers/Roots/Inequalities  92  In a certain sequence, each term, starting with the 3rd term  Sequences  93  x=2y, what is the value of x2y?  Absolute Values/Modules/Inequalities  94  If 6xy = x2y + 9y, what is the value of xy?  Algebra  95  One kilogram of a certain coffee blend consists of x  Word Problems/Mixture Problems  96  If a, b, and c are positive integers such that 1/a + 1/b = 1  Fractions/Ratios/Decimals/Inequalities  99  The Range of Set A is R. A number having equal value to R  Statistics and Sets Problems  100  If x, y, and z are integers, and x < y < z, is z y = y  Statistics and Sets Problems  101  In the table above is shown the percent reduction in the  Percent and Interest Problems/Word Problems  102  Is the perimeter of triangle ABC greater than 20? (1)  Geometry  103  What is the probability that rs=r?  Probability  104  If zy < xy < 0, is  x  z  + x = z?  Absolute Values/Modules/Inequalities  105  x and y are positive integers such that x=8y+12, what is the  Number Properties/Divisibility/Multiples/Factors  106  Ashok and Brian are both walking east along the same path  Distance/Rate Problems  107  If x, y and z are integers and xy + z is an odd integer, is  Number Properties  108  Is (7x)^1/2 an integer?  Roots/Number Properties  109  In a certain building, 1/5 of the offices have both a window  Overlapping Sets 
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Collection of Questions: PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS; 9 Devil's Dozen!!!; 10 Number Properties set., 11 New DS set.
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Re: 100 Hardest Data Sufficiency Questions [#permalink]
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Re: 100 Hardest Data Sufficiency Questions [#permalink]
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30 Oct 2013, 03:44
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Are any of these problems from GMAT prep? If there are any problems from GMAT prep, could you please highlight them with a different colour under the rank column.
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Re: 100 Hardest Data Sufficiency Questions [#permalink]
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30 Oct 2013, 03:51



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25 Nov 2013, 06:57
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Hi,
If possible can you make these topics hyperlink which redirects to concepts or may be question bank on same topic???
Just a thought.
Thanks.



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25 Nov 2013, 13:22
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Are these questions available in single file ?



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26 Nov 2013, 08:37
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can we download all these probs in a single file?



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12 Apr 2014, 16:25
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Would be great if you show these attachments in the first post..
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tnx lot for questions
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10 Jul 2014, 23:54
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Thanks a lot Bunuel. Data Sufficiency is my weak area and this would surely help. Thanks!!



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02 Sep 2014, 21:59
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It should be clear fairly quickly that neither statement alone is sufficient. For a lot of students, the phrase “well it could be anything”—the kind of massive generality that should be avoided on the GMAT—will follow them all the way to E without much thought or elbow grease.



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14 May 2015, 06:45
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Thanks a lot Bunuel.
I have a question about DS strategy .
When you solve a DS question, you solve each data (1) and (2) wholy every time ?



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Great Collection. Although time taking Qs but very good to build stamina.



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31 Jul 2015, 12:01
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Thanks Bunuel for sharing this wonderful collection. DS is the toughest part IMO. From that working on tough ques is really amazing and challenging. BTW, ques no 47 & 56 are repeated. can you add any other ques in any of that place ?
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