Nine times a two digit natural number is the same as twice the number obtained by interchanging the digits of the number.If one digit of the number exceeds the other digit by 7 ,find the number.

Asked by Anjali Sahu | 28th May, 2013, 01:52: PM

Expert Answer:

Let the ten's digit of the number be y and one's digit be x
Hence, 9(10y +x) = 2(10x+y)  (1)
Also, x = y+7
Hence susbtituting the value of y in (1)
 9(10y +y+7) = 2(10(y+7)+y) 
99y + 63 = 22y + 140
77y = 77
y = 1
x = 8
Hence, number is 18

Answered by  | 28th May, 2013, 04:53: PM

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