Question

A no.consists of 2digits whose sum is 8.if 18 is added to the number its digit are reverse. find the number.

Answer 1

Let us assume the digits be x and y

Then the two-digit number is 10x + y

Given x + y = 8

           y = 8 – x ----------------1

Given (10x + y) + 18 = 10y + x

                9x + 18 = 9y

                9y – 9x = 18

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

Substitute the value of y from eqn 1 in eqn 2 

Therefore, 8 – x – x = 2

                      8 - 2x = 2

                          2x = 6

                            x = 3

Therefore,  y = 8 – 3 = 5

The two-digit number is 10x + y = (10*3) + 5 = 35