Question

sum of the digits of a two-digit number is 9. If 9 is added to the number formed by reversing
digits, then the result is thrice the original number. Find the original number.
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Answer 1

Step-by-step explanation:

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x + y = 9

Number = 10x + y

When digits reversed , new no. = 10y+x

10y + x + 9 = 3(10x + y)

10y + x = 30x + 3y - 9

7y - 29x = -9

10(9-x) -29x = -9 ... (from 1)

90 -10x -29x = -9

99 = 39x

33 = 13x

x = 33/13

y = 9-x = 9 - 33/13 = (117-33)/13 = 84/13

Number = 10x+y

= (330+84)/13

= 414/13