Find the next number: 6, 11, 21, 41, 81, ?
Explanation:
Each term is twice the previous term minus 1. Thus 81×2−1=161.
Railway Reasoning Ability Quiz
Series, Coding-Decoding, Analogy and Blood Relation questions for Railway competitive exams
50
Questions
No limit
Duration
40%
To pass
1.00
Marks / correct
Instructions
- This quiz has 50 questions.
- There is no time limit on this quiz.
- You need 40% to pass.
- There is no negative marking.
- You can mark questions for review and return to them before submitting.
- Correct answers and explanations are shown after you submit.
Sample Questions & Answers
A preview of 12 questions from this quiz, each with the correct answer and a written explanation. Attempt the full, timed quiz to be scored and earn XP.
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Question 1 -
Question 2 Find the missing number: 4, 9, 19, 39, 79, ?
Explanation: Each term is twice the previous term plus 1. Hence 79×2+1=159. -
Question 3 What is the next number: 1, 3, 7, 15, 31, ?
Explanation: Each term is 2×previous+1. Therefore 31×2+1=63. -
Question 4 Find the missing number: 14, 18, 27, 43, 68, ?
Explanation: The differences are 4, 9, 16 and 25. The next difference is 36, so 68+36=104. -
Question 5 Find the next number: 100, 96, 87, 71, 46, ?
Explanation: The successive subtractions are 4, 9, 16 and 25. Subtracting 36 from 46 gives 10. -
Question 6 Find the missing number: 3, 6, 18, 72, 360, ?
Explanation: The multipliers are 2, 3, 4 and 5. The next multiplier is 6, so 360×6=2160. -
Question 7 What is the next number: 2, 9, 28, 65, 126, ?
Explanation: The terms follow n³+1 for n=1,2,3,4,5. The next is 6³+1=217. -
Question 8 Find the missing term: 7, 10, 16, 28, 52, ?
Explanation: The differences double: 3, 6, 12 and 24. The next difference is 48, giving 52+48=100. -
Question 9 Find the previous number: ?, 13, 27, 55, 111, 223
Explanation: Each term is twice the previous term plus 1. Since 13=2×6+1, the previous number is 6. -
Question 10 Find the next letter: B, E, I, N, T, ?
Explanation: The jumps are +3,+4,+5,+6. The next jump is +7; T plus 7 wraps to A. -
Question 11 Find the missing letter: Y, V, R, M, G, ?
Explanation: The backward jumps are 3,4,5,6. The next is 7; G(7)−7 wraps to Z. -
Question 12 Find the next alphanumeric term: C3, F6, J10, O15, ?
Explanation: Letter positions and numbers increase by 3,4,5 and then 6. The next position is 21, so U21.
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Frequently Asked Questions
This quiz has 50 questions and no time limit.
You need at least 40% to pass this quiz.
No, there is no negative marking on this quiz.
Yes. You can attempt this quiz again at any time, though first-attempt XP bonuses apply only once.