Question

The digit of two digit number differ by 3 if the digit are interchange d and the resulting number is added to the original number we get 99 what be the original number

Answer 1

Let ones digit be x          original no. is 10(x - 3) + x
 the other digit = x-3    therefore the new no. becomes
                                          10x + (x - 3)
the equation formed will be
10(x - 3) + x + 10x + (x - 3)=  99
or 10x - 30 + x +10x + x - 3 = 99
or 22x - 33 = 99
or 22x = 99 + 33
or 22x = 132
or x = 6

therefore the other digit is x - 3
                                       = 6 - 3
                                       =  3

thus the reqired no. is 36 and 63