Question

If the difference between a two- digit number 'ab' and the new number obtained by reversing its digits is taken as cd, then express cd in terms of a and b.

• A. 11(a - b)
• B. 9 (a + b)
• C. 9(a - b)
• D. 11 (a + b)

Answer 1

The correct option is C 9(a - b)

We are taking a 2 digit number ab.
The difference of original number and the number formed after reversing the digits is taken as cd, i.e.,

cd = (10a + b) - (10b + a) (assuming a > b)
cd = 9(a - b)