alleryStart learning →5 : 24 :: 8 : ?
- 81
- 63
- 48
- 56
Show answer and solution
Correct answer: B. 63
Pattern: n² - 1. 5² - 1 = 24. 8² - 1 = 63.
RRB Group D Series — practice questions
Explore 27 free Series questions in RRB Group D Reasoning. Open each question or exercise to read its content, reference answers and available explanation.
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Showing questions 1–27 of 27.
5 : 24 :: 8 : ?Read the answer and worked solution →In a string, the 6th element to the left of the 15th element from the left is the same as which position from the left?Read the answer and worked solution →Find the next number in the series: 4, 9, 20, 43, ?Read the answer and worked solution →What comes next in the series: 6C, 10F, 14I, 18L, ?Read the answer and worked solution →Find the next term of the series: 3B, 9F, 27J, ?Read the answer and worked solution →Find the next term of the series: 33, 38, 48, 53, ?Read the answer and worked solution →Find the next term of the series: T, A, S, B, R, C, ?Read the answer and worked solution →Match each proposition form to its letterRead the answer and worked solution →Universal or particular? Affirmative or negative?Read the answer and worked solution →Affirmative or negative?Read the answer and worked solution →Naming the formRead the answer and worked solution →True or false: what conversion allowsRead the answer and worked solution →Tap every inference that is actually validRead the answer and worked solution →Complete the four formsRead the answer and worked solution →True or false: what a universal claim coversRead the answer and worked solution →Deduction or induction?Read the answer and worked solution →Order the steps: test a syllogismRead the answer and worked solution →True or false: reasoning from two premisesRead the answer and worked solution →Assertion and reasonRead the answer and worked solution →Two are true, one is notRead the answer and worked solution →Three of these are wrong. Find the one that holds.Read the answer and worked solution →Flip and pair: letter with statementRead the answer and worked solution →Spot the one that does not belongRead the answer and worked solution →Deduction against inductionRead the answer and worked solution →Tap every statement that follows from 'All cats are animals'Read the answer and worked solution →Complete the conversion ruleRead the answer and worked solution →Which reversal is safe?Read the answer and worked solution →
Worked practice questions
In a string, the 6th element to the left of the 15th element from the left is the same as which position from the left?
- 7th from the left
- 9th from the left
- 8th from the left
- 10th from the left
Show answer and solution
Correct answer: B. 9th from the left
1. The 6th element to the LEFT of the 15th element means we move 6 positions left of position 15.
2. 15 - 6 = 9.
3. So it is the 9th element from the left.
_Source: RRB Group D CEN-02/2018 PYQ, Q.10._
Find the next number in the series: 4, 9, 20, 43, ?
- 100
- 90
- 92
- 82
Show answer and solution
Correct answer: B. 90
1. 4 x 2 + 1 = 9; 9 x 2 + 2 = 20.
2. 20 x 2 + 3 = 43.
3. 43 x 2 + 4 = 90.
_Source: RRB Group D CEN-02/2018 PYQ, Q.61._
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