Q10 of 25 Page 91

The sum of a two-digit number and the number obtained by interchanging its digits is 99. Find the number.

Let the unit digit be 'x' and digit at ten's place be 'y'


Original Number = 10y + x


Number obtained by interchanging digits = 10x + y


Given,


10y + x + 10x + y = 99


⇒ 11x + 11y = 99


⇒ x + y = 9


If x = 1, y = 8 and number is 18


If x = 2, y = 7 and number is 27


If x = 3, y = 6 and number is 36


If x = 4, y = 5 and number is 45


If x = 5, y = 4 and number is 54


If x = 6, y = 3 and number is 63


If x = 7, y = 2 and number is 72


If x = 8, y = 1 and number is 81


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