Explanation:

Let’s break it down step by step:

- Start with 24.

- Next number is 8. That’s a big drop. 24 to 8 (divided by 3).

- Then 8 to 12. 8 × 1.5 = 12.

- Next: 12 to 18. 12 × 1.5 = 18.

- Then 18 to 36. 18 × 2 = 36.

- Last, 36 to 90. 36 × 2.5 = 90.

Here's what stands out:

- The pattern after 8 jumps is “times 1.5.” But the move from 24 down to 8 doesn’t fit the multiplying pattern at all.

- 24 ? 8 (÷3). That’s the odd step out.

Option check:

- 18 fits the pattern (12 × 1.5).

- 36 fits (18 × 2).

- 12 fits (8 × 1.5).

- 8 does not fit the pattern. If you followed a series of multiplication increases, the right number would be 36, not 8.

So:

Option 4, 8, is the wrong number.