Read the row of digits below from left to right.
7 4 2 5 9 1 6 3 8 8 5 2 0 3 7 6 1 4 9 6 6 2 5
Take every two neighbouring digits of the row as a pair (1st and 2nd, 2nd and 3rd, and so on). How many of these pairs differ by 3?
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → 9
Each digit and the digit just after it form a pair, so the pairs are neighbours in the row. Going from left to right, the difference of every pair is found; the pairs whose difference is 3 (either way) are:
7, 4 (1st and 2nd digits)
2, 5 (3rd and 4th digits)
6, 3 (7th and 8th digits)
8, 5 (10th and 11th digits)
5, 2 (11th and 12th digits)
0, 3 (13th and 14th digits)
1, 4 (17th and 18th digits)
9, 6 (19th and 20th digits)
2, 5 (22nd and 23rd digits)
Every other neighbouring pair has a difference other than 3.
So the answer is 9.