If 2 is added to each odd digit and 3 is subtracted from each even digit in the number 7516438, what will be the difference between the greatest and smallest digits in the new number thus formed?​

Given: 7516438.

Add 2 to each odd digit and subtract 3 from each even digit.

7 is odd → 7 + 2 = 9

5 is odd → 5 + 2 = 7

1 is odd → 1 + 2 = 3

6 is even → 6 - 3 = 3

4 is even → 4 - 3 = 1

3 is odd → 3 + 2 = 5

8 is even → 8 - 3 = 5

So, the new digits are: 9, 7, 3, 3, 1, 5, 5

Greatest = 9

Smallest = 1

Difference = 9 - 1 = 8

So, 8 will be the difference between the greatest and smallest digits in the new number thus formed.

Thus, correct option is (b).