This page covers SSC CHSL Data Sufficiency β Reasoning with complete concept notes, 23 graded practice MCQs, key points and exam-specific tips. Free to study.
Data Sufficiency is a unique question type where you don't solve the problem completely. Instead, you determine whether the given information is enough to answer the question. Think of it as being a detective - you need to check if the clues are sufficient to solve the case.
In SSC CGL, data sufficiency questions typically provide a question followed by two statements (I and II).
Your job is to decide which combination of statements can answer the question. The standard answer choices are:
A) Statement I alone is sufficient
B) Statement II alone is sufficient
C) Both statements together are sufficient
D) Neither statement is sufficient
E) Each statement alone is sufficient
Key Rules: Never assume information not given. Don't make calculations unless necessary - just check if calculation is possible.
Focus on 'Can I solve?' not 'What is the answer?'. Remember that 'sufficient' means you can find a unique answer, not multiple possibilities.
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Exam Patterns
What examiners ask β read before attempting PYQs
SSC CGL asks 2-3 data sufficiency questions per paper. Common topics include ages, profit-loss, time-work, geometry, and number problems. Questions often test logical thinking more than mathematical computation.
Powerful Shortcut: Use the SCAN method - S(can I solve with Statement I alone?), C(an I solve with Statement II alone?), A(re both needed together?), N(ot sufficient even together?). This systematic approach prevents confusion and saves time.
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Worked Example
Solve this step-by-step before moving on
1
Step 1
Check Statement I alone
Statement I gives us: Ram = Shyam + 5
This has two unknowns but only one equation. We cannot find Ram's exact age.
Statement I alone: NOT SUFFICIENT
2
Step 2
Check Statement II alone
Statement II gives us: Ram + 10 = 2 Γ (Shyam's current age)
Again, two unknowns, one equation. Cannot find exact ages.
Statement II alone: NOT SUFFICIENT
3
Step 3
Check both statements together
From I: Ram = Shyam + 5, so Shyam = Ram - 5
From II: Ram + 10 = 2 Γ Shyam
Substituting: Ram + 10 = 2(Ram - 5)
Ram + 10 = 2Ram - 10
20 = Ram
Both statements together give us Ram's age as 20 years.
Answer: C) Both statements together are sufficient
Common Mistake: Students often try to solve the complete problem instead of just checking sufficiency. This wastes time and can lead to wrong conclusions. Another trap is assuming obvious information that isn't stated - stick strictly to what's given.
Remember: In data sufficiency, your goal is to be a judge, not a calculator. Judge whether the evidence is enough to reach a verdict.
Test Data Sufficiency β Reasoning under exam conditions
Statements:
I. Some athletes are vegetarians.
II. All vegetarians are health-conscious.
Question: Are all athletes health-conscious?
Which of the following is correct?
(A) Yes, all athletes are health-conscious.
(B) No, not all athletes are health-conscious.
(C) Cannot be determined from the given statements.
(D) The statements are contradictory.
Practice 2easy
Statements:
I. No politician is honest.
II. All honest people are trustworthy.
Question: Can a politician be trustworthy?
(A) Yes, definitely
(B) No, definitely not
(C) Yes, but not necessarily through honesty
(D) Cannot be determined
Practice 3easy
Statements:
I. All teachers are educated.
II. Some educated people are not doctors.
Question: Is it possible that all teachers are doctors?
Which of the following is correct?
(A) Yes, it is possible.
(B) No, it is not possible.
(C) Cannot be determined from the given statements.
(D) The statements are contradictory.
Practice 4easy
Statements:
I. All roses are flowers.
II. Some flowers are red.
III. All red things are beautiful.
Question: Are all roses beautiful?
Which of the following is correct?
(A) Yes, all roses are beautiful.
(B) No, not all roses are beautiful.
(C) Cannot be determined from the given statements.
(D) Only some roses are beautiful.
Practice 5easy
Statements:
I. Some athletes are vegetarians.
II. All vegetarians are health-conscious.
Question: Are all athletes health-conscious?
(A) Yes, all athletes are health-conscious
(B) No, not all athletes are health-conscious
(C) Cannot be determined from the given statements
(D) Yes, and this must be true
Practice 6easy
Statements:
I. All teachers are educated.
II. Some educated people are not doctors.
Question: Is it possible that all teachers are doctors?
(A) Yes, it is possible
(B) No, it is not possible
(C) Cannot be determined from the given statements
(D) Yes, and it must be true
Practice 7easy
Statements:
I. All engineers are problem-solvers.
II. No problem-solver is lazy.
Question: Can an engineer be lazy?
Which of the following is correct?
(A) Yes, an engineer can be lazy.
(B) No, an engineer cannot be lazy.
(C) Cannot be determined from the given statements.
(D) The statements are contradictory.
Practice 8easy
Statements:
I. No politician is honest.
II. All honest people are trustworthy.
Question: Can a politician be trustworthy?
Which of the following is correct?
(A) Yes, definitely.
(B) No, definitely not.
(C) Cannot be determined from the given statements.
(D) The statements are insufficient.
Practice 9easy
Statements:
I. All doctors are professionals.
II. Some professionals are not engineers.
Question: Can a doctor be an engineer?
(A) No, a doctor cannot be an engineer
(B) Yes, a doctor can be an engineer
(C) All doctors must be engineers
(D) Cannot be determined
Practice 10easy
Statements:
I. All flowers are plants.
II. Some plants are not green.
Question: Must all flowers be green?
(A) Yes, all flowers must be green
(B) No, not all flowers must be green
(C) All flowers are definitely not green
(D) Cannot be determined from the given statements
Practice 11medium
Five boxes are arranged in a row. Statement I: Box P is to the left of Box Q. Statement II: Box R is immediately to the right of Box P. Which box is in the middle position?
A) Statement I alone is sufficient
B) Statement II alone is sufficient
C) Both statements together are sufficient
D) Even both statements together are not sufficient
Practice 12medium
A company has employees in three departments: Sales, Marketing, and Operations. Statement I: The number of Sales employees is 20% more than Marketing employees. Statement II: The number of Operations employees is 15% less than Marketing employees. What is the ratio of Sales to Operations employees?
A) Statement I alone is sufficient
B) Statement II alone is sufficient
C) Both statements together are sufficient
D) Even both statements together are not sufficient
Practice 13medium
Five friendsβA, B, C, D, Eβsit in a row. Is C sitting in the middle position?
Statement I: A and E are at the two ends.
Statement II: B is immediately to the left of C, and D is immediately to the right of C.
Which statement(s) is/are sufficient to answer the question?
Practice 14medium
In a family of 6 people, there are three married couples. Statement I: A is the father of B and C. Statement II: D is the mother of E and F. Is A married to D?
A) Statement I alone is sufficient
B) Statement II alone is sufficient
C) Both statements together are sufficient
D) Even both statements together are not sufficient
Practice 15medium
A shopkeeper sells three types of items: X, Y, and Z. Is the profit on item Y greater than the profit on item X?
Statement I: The profit margin on Y is 25% and on X is 20%.
Statement II: The cost price of X is βΉ100 and the cost price of Y is βΉ80.
Which statement(s) is/are sufficient to answer the question?
Practice 16medium
A person starts at point X and travels. Statement I: The person travels 8 km North, then turns right and travels 6 km. Statement II: After reaching the point described in Statement I, the person turns left and travels 4 km. Where is the person now relative to point X?
A) Statement I alone is sufficient
B) Statement II alone is sufficient
C) Both statements together are sufficient
D) Even both statements together are not sufficient
Practice 17medium
In a group of students, some study Math, some study Science. Statement I: 40% of students study Math. Statement II: 30% of students study both Math and Science. What percentage of students study only Science?
A) Statement I alone is sufficient
B) Statement II alone is sufficient
C) Both statements together are sufficient
D) Even both statements together are not sufficient
Practice 18medium
In a family, there are 4 children. Is Priya older than Arjun?
Statement I: Priya is older than Rohan, and Rohan is older than Arjun.
Statement II: Arjun is the youngest among the four children.
Which statement(s) is/are sufficient to answer the question?
Practice 19hard
A train travels from Station A to Station B. Statement I: The train travels at 60 km/h for the first half of the distance. Statement II: The train travels at 90 km/h for the second half of the distance. Can we determine the average speed of the train for the entire journey?
(A) Statement I alone is sufficient.
(B) Statement II alone is sufficient.
(C) Statements I and II together are sufficient.
(D) Even both statements together are not sufficient.
Practice 20hard
In a group of students, Statement I: 60% are proficient in English. Statement II: 75% are proficient in Mathematics. Statement III: 50% are proficient in both English and Mathematics. What percentage of students are proficient in at least one of the two subjects?
(A) Statement I alone is sufficient.
(B) Statements I and II together are sufficient.
(C) Statements I, II, and III together are sufficient.
(D) Even all three statements together are not sufficient.
3 more practice questions in the Study Panel
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