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Pair of Linear Equations in Two Variables
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27/05/2021 11:51 am
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The sum of the digits of a two-digit number is 9. Also, nine times this number is twice the number obtained by reversing the order of the digits. Find the number.
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27/05/2021 11:53 am
Let the unit digit and tens digit of a number be x and y respectively.
Then, Number (n) = 10B + A
N after reversing order of the digits = 10A + B
According to the given information, A + B = 9…………………….(i)
9(10B + A) = 2(10A + B)
88 B – 11 A = 0
-A + 8B = 0 …………….. (ii)
Adding the equations (i) and (ii) we get,
9B = 9
B = 1 …………………….(3)
Substituting this value of B, in the equation (i) we get A= 8
Hence the number (N) is 10B + A = 10 x 1 +8 = 18