Every year, thousands of hopeful students sit for the BITS Admission Test (BITSAT) – a computer‑based test used by BITS Pilani and its other campuses to choose students for engineering and science programmes. Unlike most entrance exams, BITSAT has a bonus round that lets you attempt an additional 12 questions after you have finished the main paper.
I’m often asked whether going after those extra questions is worth it. Having been through the process myself, my answer is that it depends on your current score buffer, time left, and mental state. In this long read, I walk through the rules, run some numbers, and share mental models to help you make an informed choice.
What makes the bonus round a gamble instead of a reward?
When I first heard about BITSAT’s bonus questions, I saw them as a generous gift. In reality, they are more like a high‑stakes gamble. After you answer all 130 questions in the main paper, the system presents a button to open 12 more questions. If you click it, you will not be able to go back to change any of your earlier answers; you simply attack the new questions and hope you come out ahead.
The exam’s marking scheme gives +3 marks for a correct answer, –1 mark for an incorrect answer and 0 for leaving a question unattempted. With 130 questions, the main paper has a maximum of 390 marks. If you open the bonus round and solve all questions, the theoretical ceiling goes up to 426 marks. That gap of 36 marks tempts many students.
But before you chase the top score, you need to ask a more practical question:
In my experience, most students think about whether they can solve the bonus questions. The right way to think about it is whether the expected value of entering the bonus round is positive for you. The rest of this article breaks down that expected value using simple maths and some behavioural psychology.
How does the bonus section work in BITSAT?
Before diving into strategy, you must understand the mechanics. The rules are straightforward and unforgiving:
- Complete every question in the main paper: The BITSAT paper is divided into Physics (30 questions), Chemistry (30 questions), Mathematics/Biology (40 questions), English Proficiency (10 questions) and Logical Reasoning (10 questions). You must attempt (mark) all 130 questions to see the bonus option. Leaving even one unattempted question blocks the bonus round.
- No going back: Once you opt in, your responses to the first 130 questions are locked. You won’t be able to review or change them. This means that any careless mistakes remain.
- Twelve extra questions appear: According to the official guidance, these 12 questions are drawn from the core subjects. Many coaching websites mention that four questions each are picked from Physics, Chemistry and Mathematics/Biology. Other sources say three questions from each of four areas (including English and logical reasoning). The pattern can vary by year, but they are always subject‑based.
- Same marking rules: The bonus questions carry +3 for a correct answer and –1 for a wrong answer, just like the main paper.
These rules create a point of no return: you give up the safety of revisiting your earlier answers for a chance at higher marks. Make sure you know where you stand before clicking that button.
Overview of the BITSAT paper and bonus round
| Component | Questions | Marks per question | Total marks |
| Physics | 30 | +3 / –1 | 90 |
| Chemistry | 30 | +3 / –1 | 90 |
| Mathematics/Biology | 40 | +3 / –1 | 120 |
| English Proficiency | 10 | +3 / –1 | 30 |
| Logical Reasoning | 10 | +3 / –1 | 30 |
| Main paper total | 130 | 390 | |
| Bonus round | 12 (distribution varies) | +3 / –1 | 36 |
| Grand total | 142 | 426 |
The table shows why the bonus section looks attractive: 12 additional questions can theoretically add 36 marks to your tally. But there is a hidden cost: you must first answer every main‑paper question.
How large should your score buffer be before you guess to open the bonus?
What is a “score buffer”?
I use this term to describe the cushion you need in the main paper to absorb any losses from guessing the remaining questions. Think of it as the difference between your current secure score and the score you need for admission. If you open the bonus round but then lose marks because of wild guesses, your buffer erodes.
Why random guessing is a coin toss at best
Suppose you have ten unattempted questions at the end. To open the bonus section, you have to mark all ten. Assuming the probability of guessing correctly on a four‑option multiple‑choice question is 25%, the expected value of each blind guess is:
- Probability correct: 0.25
- Marks for correct: +3
- Probability wrong: 0.75
- Marks for wrong: –1
Expected value = (0.25 × 3) + (0.75 × –1) = 0 marks. On average, a random guess neither helps nor hurts. However, the variance is high. Out of 10 guesses, the most probable outcome is two or three correct answers and seven or eight wrong ones. You might get zero net marks, but you could also lose –5 or –6 marks if luck is not in your favour.
A simple example
Let’s say you have solved 120 questions confidently and leave 10 unattempted. To access the bonus, you guess these 10. Statistically, you expect around 2.5 of them to be correct and 7.5 wrong (EV = 0). However, a bad streak of guesses could cost you several marks. This is why you need a score buffer: if you are already sitting on a high score, a small negative fluctuation will not hurt your overall rank; if you are barely above the cut‑off, the risk is unacceptable.
When does the maths favour taking the bonus questions?
Breaking even after the guesses
Assume you end up losing 4 marks while guessing to open the bonus. Each bonus question carries +3 marks for a correct answer and –1 for a wrong answer. To regain the lost 4 marks, you need at least two correct answers out of 12 (2 × 3 = 6, minus any wrong answers). Two correct answers out of 12 is achievable if you are well‑prepared, but far from certain.
Keep in mind that many students and teachers report that the bonus questions are often slightly tougher or trickier than the main paper. They may include more time‑consuming calculations or less familiar concepts. Therefore you should not count on hitting a high accuracy rate if you are already exhausted.
The 5‑question rule of thumb
Over the years, I have found this simple guideline useful:
- Fewer than five unattempted questions: If you have only one to four unattempted questions, it is relatively safe to take educated guesses to access the bonus. Your potential loss is capped at a few marks, and the upside of +36 could be worth it.
- Five to ten unattempted questions: Proceed with caution. Here, guessing starts to introduce volatility. If you can eliminate one or two options on each question based on partial knowledge, the odds improve. If you must guess blindly, think twice.
- More than ten unattempted questions: It rarely makes sense to open the bonus round. You would have to guess at least ten times, increasing your risk of losing marks. You also signal that you were not comfortable with the main paper; diving into tougher questions is unlikely to rescue your score.
What mental and emotional factors come into play?
Strategy isn’t only about numbers. Your mind plays a major role after 170 minutes of intense problem‑solving.
1) Decision fatigue
Decision fatigue is the idea that the quality of our decisions declines as we make more of them. Studies in behavioural science show that when we are overloaded with choices, we become mentally exhausted and start taking shortcuts. In the context of BITSAT, by the time you reach the last 20 minutes, your brain has answered 130 questions and managed time pressure. This exhaustion can lead to imprecise guesses, misreading questions, or mis‑clicking options.
2) Test anxiety and panic
Research on test anxiety shows that students with higher anxiety levels tend to perform worse on exams. Anxiety interferes with working memory, making it harder to focus and process information. When you rush to guess unattempted questions just to open the bonus round, you may heighten that anxiety. Panic can cause you to click options without fully reading them or to waste precious time second‑guessing yourself.
3) The sunk‑cost fallacy
There is also the sunk‑cost fallacy, which refers to our tendency to continue with a course of action simply because we have already invested time or effort. In the exam hall, many students think, “I’ve already solved 125 questions; I might as well guess the remaining five to open the bonus.” That thinking is flawed. Your earlier effort is a sunk cost. The only question that matters is whether guessing those five questions improves your expected score.
Who should consider the bonus questions?
Based on years of observing and mentoring students, I have created three archetypes. See where you fit.
| Persona | Current status | Time left | Recommended action | Rationale |
| A. The “300+ Secure” candidate | You have attempted 125+ questions with high accuracy and feel confident. | More than 20 minutes remain. | Proceed to the bonus. | Your base score is already strong, and you need only a few guesses to access the bonus. The upside of +36 marks outweighs the modest risk. |
| B. The “Borderline Scrambler” | You have attempted around 110 questions, leaving 20 unattempted. | Around 15 minutes remain. | Do not open the bonus. Use the remaining time to review your answers. | Guessing 20 questions is statistically dangerous. The negative marking is likely to erode your hard‑earned score. It is better to ensure accuracy on your 110 attempts. |
| C. The “Gambler” | You have attempted 115 questions and left 15 unattempted. | About 25 minutes remain. | Evaluate before deciding. | If you can eliminate one or two options on many of the unattempted questions, the expected value becomes positive. If they are pure guesses, stick to reviewing. |
How can you make the decision in the exam hall?
When I sat for BITSAT, I made a mental checklist. Over time, I refined it into a simple flowchart you can follow in the last half‑hour of the exam:
- Do I have at least 15–20 minutes left? If you have less than 10 minutes, there is little time to both guess and attempt 12 more questions. It is safer to review your main answers.
- How many unattempted questions do I have? If it’s fewer than 10, and ideally fewer than 5, the risk is manageable. If it’s more than 10, reconsider.
- Am I confident in my first 120 answers? Think about whether you have reviewed them. If there are doubts about careless errors, invest time in checking instead of chasing more marks.
- Have I eliminated options on the remaining questions? If you can narrow each unattempted question to two choices, your chance of guessing correctly jumps from 25% to 50%. That makes the expected value of guessing positive.
If you answer “yes” to all four checks, go ahead: carefully select answers for the remaining questions, submit the main paper, and tackle the bonus round. Otherwise, secure your existing score.
Don’t let fear of missing out dictate your strategy
It’s easy to be dazzled by the prospect of 426 marks. But BITSAT is designed such that only a small fraction of candidates finish the main paper early enough with enough accuracy to make the bonus worthwhile. The bonus section is a tool for rank improvement, not score rescue. It rewards those who have already saturated the main paper and still have mental bandwidth left.
Most students will find better returns by minimizing errors in the first 130 questions. As per my experience, leaving a question blank can be smarter than guessing because random guessing has zero expected value and high variance. Your primary goal should be to reach a solid score (around 300+ for top branches) before even thinking about the bonus. Only when you have the time, the confidence, and a sufficient buffer should you hit that bonus button.
Final advice from someone who has been there
When I took BITSAT, I decided not to open the bonus round, even though the button was flashing at me. I had about six unattempted questions and only ten minutes left. I realised I would probably lose more marks guessing and then rush through the bonus. I spent the remaining time checking my calculations instead. In the end, I scored above 330 and got the branch I wanted.
Looking back, the bonus round is an ingenious feature. It adds excitement and differentiates the very top performers. But it is not a magical escape route. Make your decision based on logic, not fear of missing out. Keep in mind that the extra 12 questions are an opportunity only if you have already done the hard work of mastering the main paper.
If you’re still curious about how people approach the bonus questions, check out this short video that discusses strategies and pitfalls: BITSAT bonus questions explained.
Good luck with your preparation! Focus on building strong fundamentals, practise under timed conditions, and keep your nerves in check. When the bonus button appears, you’ll know exactly what to do.
