Question

The šum of 2 digit number is 13 if the number is subtracted from the 1 obtained by interchangeing the digits the result is45

Answer 1

Let us assume the digits be x and y

Then the two-digit number is 10x + y

Given x + y = 13

           y = 13 – x --------------1

Interchange the two-digit number, get 10y + x

Given 10y + x – (10x + y) = 45

            9y – 9x = 45

              y – x = 5 --------------2

Substitute the value of y from eqn 1 in eqn 2

13 – x – x = 5

13 – 2x = 5

2x = 8

x = 4

Therefore, y = 13 – 4 = 9

The two-digit number = 10x + y = (10 * 4) + 9 = 49