Read the row of digits below from left to right.
2 0 5 3 8 5 2 5 5 3 9 1 2 4 5 0 1 2 0 0 9 8
Take every two neighbouring digits of the row as a pair (1st and 2nd, 2nd and 3rd, and so on). In how many of these pairs are both digits odd?
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → 5
Each digit and the digit just after it form a pair. Going from left to right, the pairs in which both digits are odd (1, 3, 5, 7 or 9) are:
5, 3 (3rd and 4th digits)
5, 5 (8th and 9th digits)
5, 3 (9th and 10th digits)
3, 9 (10th and 11th digits)
9, 1 (11th and 12th digits)
Every other neighbouring pair has at least one even digit.
So the answer is 5.