Find the missing term in the following series? 0, 2, 9, ?, 50, 90, 147
2025
Find the missing term in the following series?
0, 2, 9, ?, 50, 90, 147
Answer: B. 24 — Key idea: examine first and second differences. Compute first differences between consecutive terms: 2 (2−0), 7 (9−2), ? (unknown), 40 (90−50), 57 (147−90).…
- A.
20
- B.
24
- C.
27
- D.
36
Attempted by 97 students.
Show answer & explanation
Correct answer: B
Key idea: examine first and second differences.
Compute first differences between consecutive terms: 2 (2−0), 7 (9−2), ? (unknown), 40 (90−50), 57 (147−90).
Compute known second differences where possible: 7−2 = 5 and 57−40 = 17. These second differences fit an arithmetic progression that increases by 3 each step.
Fill in the missing second differences to make the sequence 5, 8, 11, 14, 17 (each term +3).
So the missing first difference is 7 + 8 = 15, and the missing term is 9 + 15 = 24.
Answer: 24