Directions: Find the wrong number in the series. 2880, 480, 92, 24, 8, 4, 4
Aptitude
Odd Man Out and Series
Difficulty: Medium
Choose an option
-
A480
-
B92
-
C24
-
D8
-
E4
Answer
Correct Answer: 92
Explanation
### Concept & Logic
The sequence rapidly descends and then plateaus. This usually indicates division by a decreasing integer or sequence.
### Step-by-Step Solution
1. Let's find the division ratio between consecutive terms, starting from the left:
- $2880 / 480 = 6$ (So the rule is divide by 6)
2. Let's test the end of the sequence to confirm:
- $8 / 4 = 2$ (Rule is divide by 2)
- $4 / 4 = 1$ (Rule is divide by 1)
3. The pattern of divisors is clearly $6, 5, 4, 3, 2, 1$.
4. Let's apply this division pattern from the beginning:
- $2880 / 6 = 480$
- $480 / 5 = 96$. (The sequence has 92 here, making it the wrong number).
5. Verify the next steps using the corrected number $96$:
- $96 / 4 = 24$ (Matches)
- $24 / 3 = 8$ (Matches)
### Exam Strategy & Shortcut
Working from right to left (the smaller numbers) is often faster. $4 \times 1 = 4$, $4 \times 2 = 8$, $8 \times 3 = 24$, $24 \times 4 = 96$. You hit the wrong number ($92$) much faster without doing mental division on $2880$.
### Common Pitfall
Trying to find subtraction patterns for numbers scaling down this dramatically, which wastes time.
### Final Answer
Therefore, the correct answer is **92**.