RRB Group D CBT strategy: 100 questions in 90 minutes

The RRB Group D CBT gives you 90 minutes for 100 questions, about 54 seconds each. The questions are school-level, so most candidates can solve most of them given enough time. The difference between selection and a near miss is usually how well you use the clock and how few careless mistakes you make.

A strategy is not something you invent in the exam hall. You build it in mocks, test it, and arrive with a plan you have already used twenty times.

A time budget

These add up to 80–88 minutes, leaving a small buffer. GK and science are quick: you know the answer or you don't. That frees time for maths and reasoning, where you have to work things out.

Adjust these times to your strengths in mocks. If maths is your strong side, it may need less time than reasoning.

Which section first?

Many candidates start with General Awareness and Science: quick marks and a calm start. Others start with their strongest section, whatever it is. Both work. Try each order in at least three mocks and keep the one that gives your best score and accuracy.

What does not work is changing your order on exam day because of nerves.

The two-round method

1. Round 1: answer every question you can solve quickly. Mark for review anything that needs long working.
2. Round 2: go back to marked questions with the time left, easiest first.
3. Last 5 minutes: look again at questions you narrowed to two options.

A simple rule for Round 1: if you cannot see how to start a question within about 20 seconds, mark it and move on. You are not giving up on it. You are refusing to let one question steal the time of three easier ones.

Guessing with one-third negative marking: the maths

Each question has four options. A right answer earns 1 mark; a wrong one costs ⅓. Here is the average result of guessing:

So a blind guess gains nothing on average and only adds risk. Once you can rule out two options, a guess is clearly worth taking.

A worked example

Suppose a candidate is sure of 70 answers (assume all correct), has narrowed 15 more to two options each, and has no idea on the last 15.

• Plan A, only the sure ones: 70 marks.
• Plan B, sure ones plus the 15 two-option guesses: on average 70 + 15 × ⅓ = 75 marks.
• Plan C, Plan B plus 15 blind guesses: still about 75 on average, but the score can swing several marks either way.

Plan B is the sensible choice: it adds marks without adding needless risk. Read more in our guide on negative marking.

Set your own targets

Take five full mocks, then fill this in:

Aim for accuracy above 90%. Accuracy is right answers divided by attempts: 72 right out of 80 attempted is 72 ÷ 80 = 90%. More attempts with poor accuracy lose marks, as the pattern guide shows with worked scores in the RRB Group D exam pattern.

On the exam screen

• Read the instructions page fully. It explains the question palette colours and how marked questions are treated.
• Use the palette to jump between sections instead of scrolling question by question.
• Keep an eye on the timer at your planned checkpoints, for example "GK and science done by the 30-minute mark".
• In review, change an answer only when you can see a clear reason, such as a misread word or a calculation slip.

If your shift feels hard

• Everyone in your shift has the same paper.
• Marks are normalised across shifts.
• Collect the easy marks first. Do not let one hard section spoil the next.

Practise the rhythm

• Take mocks at the same time as your likely shift.
• Use an on-screen mock with a question palette, like the real exam.
• After each mock, spend as long checking it as you spent taking it. Our mock test guide shows how.

Quick self-check

1. A candidate gets 64 right and 15 wrong. Score? 64 − 5 = 59.
2. With two options ruled out, is a guess worth it? Yes, +⅓ of a mark on average.
3. 81 right out of 90 attempted. Accuracy? 81 ÷ 90 = 90%.
4. How long is 54 seconds × 100? 5,400 seconds = 90 minutes.

Your last two weeks

• Fix your section order and time checkpoints; stop experimenting.
• Take a full mock daily at your shift time, with the two-round method.
• Track accuracy per section and cut blind guesses to zero.
• Sleep at a fixed time so your brain is fresh at the shift hour.