“How many questions should I attempt?” is the most common question before any prelims. The honest answer: it depends on your accuracy, not on a magic number. This guide shows you the simple maths behind negative marking so you can decide for yourself.
Negative marking in major exams
| Exam | Marks per question | Penalty per wrong answer | Penalty as a fraction |
|---|---|---|---|
| IBPS PO / Clerk, SBI PO / Clerk, RBI Assistant | 1 (varies by section) | 1/4 of the question’s marks | 1/4 |
| SSC CGL Tier-I | 2 | 0.50 | 1/4 |
| SSC CGL Tier-II (Paper-I, Sections I–III) | 3 | 1 | 1/3 |
| RRB NTPC | 1 | 1/3 | 1/3 |
| UPSC Civil Services Prelims (GS) | 2 | 0.66 | 1/3 |
The one formula you need
If your accuracy is A (the share of your attempts that are correct) and the penalty fraction is p:
Net marks per attempt = A − (1 − A) × p
With a 1/4 penalty (bank exams, SSC CGL Tier-I)
| Accuracy | Net marks from 40 attempts (1 mark each) |
|---|---|
| 100% | 40.0 |
| 90% | 36 − 1.0 = 35.0 |
| 80% | 32 − 2.0 = 30.0 |
| 70% | 28 − 3.0 = 25.0 |
| 50% | 20 − 5.0 = 15.0 |
| 25% | 10 − 7.5 = 2.5 |
| 20% | 8 − 8.0 = 0 |
Two lessons:
- With a 1/4 penalty, an attempt only hurts you if your accuracy is below 20% (pure guessing among 5 options).
- But every wrong answer still costs you. Going from 90% to 70% accuracy on the same 40 attempts loses 10 marks, which is often the gap between clearing and missing the cut-off.
Should you guess?
| Situation | With 1/4 penalty | With 1/3 penalty |
|---|---|---|
| Pure blind guess, 5 options | Expected gain ≈ 0. Skip it | Expected loss. Skip it |
| Pure blind guess, 4 options | Expected gain ≈ +0.06. Barely worth it | Expected gain 0. Skip it |
| You can eliminate 1 option (5-option paper) | Expected gain ≈ +0.06 | Expected gain 0. Skip it |
| You can eliminate 2 options | Expected gain ≈ +0.17. Attempt | Expected gain ≈ +0.11. Attempt |
| 50:50 between two options | Expected gain ≈ +0.38. Attempt | Expected gain ≈ +0.33. Attempt |
Rule of thumb: attempt when you can eliminate at least two options. Never blind-guess with a 1/3 penalty.
A safe attempt range for bank prelims
There is no official “safe” number. Use this method instead:
- Take 5 full mocks and note your accuracy in each section.
- If your accuracy is 85% or above, attempt every question you can solve within the time.
- If your accuracy is 70–85%, slow down slightly: reduce attempts by 3–5 and check those you are unsure of.
- If your accuracy is below 70%, your problem is concepts, not speed. Fix weak topics before increasing attempts.
In bank prelims, the sectional cut-off matters. A high score in Reasoning cannot save a very low score in English (except in SBI Clerk Prelims, which has no sectional cut-off).
Five habits that protect your score
- Two-round approach: first round, attempt only sure questions; second round, use the remaining time on 50:50 ones.
- Mark, don’t guess: in the exam interface, mark doubtful questions for review instead of answering immediately.
- Avoid “time-sink” questions: a lengthy puzzle that takes 6 minutes is worth the same as a 30-second inequality question.
- Track silly mistakes: in your mock analysis, separate “didn’t know” from “careless”. Careless errors are the easiest marks to recover.
- Never change answers without a reason: your first answer is usually right unless you find a clear mistake.
Practise with real timing
- Free bank and SSC mock tests with negative marking and analysis
- Daily quizzes for General Awareness accuracy
Marking schemes are from the latest official notifications of each exam. Always check the notification of the exam you are writing.