Read the row of digits below from left to right.
3 4 5 2 5 5 8 5 1 2 4 4 3 5 4 4 1 4 5 3 4 1 5 8 5 1
How many 5s in this row have an even digit directly before them?
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → 5
Check every 5 in the row: the digit before it must be even (0, 2, 4, 6 or 8).
Place 3: 4 5 2 — counts
Place 5: 2 5 5 — counts
Place 6: 5 5 8 — does not count (preceded by 5, an odd digit)
Place 8: 8 5 1 — counts
Place 14: 3 5 4 — does not count (preceded by 3, an odd digit)
Place 19: 4 5 3 — counts
Place 23: 1 5 8 — does not count (preceded by 1, an odd digit)
Place 25: 8 5 1 — counts
So the answer is 5.