100 Hardest Data Sufficiency Questions

Question

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/(x-y) < 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 xy-plane, 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^n-2^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^2-2x+A is positive for all x Ax^2+1 is Algebra 54 If for any positive integer x, d 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 (x-a)^2 + (y-b)^2=16 intersect the y-axis ? 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) |x|-|y|<|x-y 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| 2|x 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 ? (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 x-2y? 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

Bunuel · Accepted Answer

DS: 100-hardest-data-sufficiency-questions-all-in-one-doc-162866.html PS: bunuel-s-100-hardest-problem-solving-questions-in-one-doc-163175.html Hope this helps.

Bunuel · Answer

They are hardest according to our timer.

Carcass · Answer

Are the hardest Bunnel? Can we safely say that? Would be a really good set of various questions to build your own stamina...

Thanks.

Carcass · Answer

Are you working on PS to I guess....

I'm thinking to collect the sets then, similar to Bunuels collection.

Regards

fozzzy · Answer

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.

Bunuel · Answer

PS is ready and will be published next week.

Bunuel · Answer

Yes, there are some questions from GMAT Prep and OG, which have appropriate tags when you follow the links.

beatthegmat05 · Answer

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.

Bunuel · Answer

Something like that is done here: new-project-review-discuss-and-get-kudos-points-153555.html Hope it helps.

vemuluri133 · Answer

Are these questions available in single file ?

kulkarnios · Answer

can we download all these probs in a single file?

JusTLucK04 · Answer

Would be great if you show these attachments in the first post.. :thumbup:

gmatonline · Answer

tnx lot for questions

ankushsetia · Answer

Thanks a lot Bunuel. Data Sufficiency is my weak area and this would surely help. Thanks!!

pannakh · Answer

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.

khamza · Answer

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 ?

ssmohanta · Answer

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

shyind · Answer

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 ?

bumpbot · Answer

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A member just gave Kudos to this thread, showing it’s still useful. I’ve bumped it to the top so more people can benefit. Feel free to add your own questions or solutions.

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100 Hardest Data Sufficiency Questions

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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/(x-y) < 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 xy-plane, 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^n-2^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^2-2x+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 (x-a)^2 + (y-b)^2=16 intersect the y-axis ?	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^3y^5/xy^2 <0 (2) \|x\|-\|y\|<\|x-y	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\| 2\|x 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 non-zero 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 five-distinct-digit 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 x-2y?	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

GMAT Data Sufficiency (DS) Questions

100 Hardest Data Sufficiency Questions

Prep Toolkit

615 to 715 in 15 Days (Ria's Strategies)

More than Quant/Verbal Abilities: Speed vs. Accuracy

745 with Only Self-Prep and GMAT Club

From 555 to 765: 210-point Improvement

Perfect 805 Score Debrief by Julia

My Rewards