If 1 is added to each odd digit and 1 is subtracted from each even digit in the number 8731542, what will be the difference between the highest and lowest digits in the number thus formed?​

Given: 8731542

Add 1 to each odd digit and subtract 1 from each even digit.

8 → even → 8 − 1 = 7

7 → odd → 7 + 1 = 8

3 → odd → 3 + 1 = 4

1 → odd → 1 + 1 = 2

5 → odd → 5 + 1 = 6

4 → even → 4 − 1 = 3

2 → even → 2 − 1 = 1

New digits: 7, 8, 4, 2, 6, 3, 1

Highest = 8

Lowest = 1

Difference:

= 8 − 1

= 7

So, 7 will be the difference between the highest and lowest digits in the number thus formed.

Thus, correct option is (d).