What is the next number? 30, 24, 18, 34, 9, 45, __________
20232024
What is the next number?
30, 24, 18, 34, 9, 45, __________
- A.
-2
- B.
4
- C.
-4
- D.
2
Attempted by 41 students.
Show answer & explanation
Correct answer: C
Key insight: after the first two subtractions of 6, the sequence alternates adding and subtracting consecutive square numbers (4², 5², 6², 7², ...).
30 − 6 = 24
24 − 6 = 18
18 + 4² (16) = 34
34 − 5² (25) = 9
9 + 6² (36) = 45
45 − 7² (49) = −4
Answer: −4