Find the next term in the following series: 1, 2, 4, 6, 7, 18, 10, 54, ?
2022
Find the next term in the following series: 1, 2, 4, 6, 7, 18, 10, 54, ?
Answer: B. 13 — ConceptA series can combine two independent subsequences. To detect the rule, separate the terms by position and test a consistent operation within each…
- A.
162
- B.
13
- C.
64
- D.
72
Attempted by 5 students.
Show answer & explanation
Correct answer: B
Concept
A series can combine two independent subsequences. To detect the rule, separate the terms by position and test a consistent operation within each subsequence.
Application
The odd-position terms are 1, 4, 7, 10, …; each term is 3 more than the preceding odd-position term.
The even-position terms are 2, 6, 18, 54, …; each term is 3 times the preceding even-position term.
The missing term is at position 9, an odd position. Continue the odd-position subsequence: 10 + 3 = 13.
Cross-check
Putting 13 after 54 preserves both independent rules: 1, 4, 7, 10, 13 increases by 3, while 2, 6, 18, 54 multiplies by 3.
Result
The next term is 13.