Question

T2.T?

Answer 1

9514 1404 393

Answer:

  63

Step-by-step explanation:

Reversing the digits changes the value by a factor of 9 times the difference in the digit values. Here, this means the digits differ by 27/9 = 3. If one digit is double the other, the higher digit is 2×3 = 6.

The number is 63.

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If you like, you can work through the algebra of it. Let the original number have tens digit x and ones digit y.

  original number value = 10x +y

  reversed number value = 10y +x

  difference of values = 27 = (10x +y) -(10y +x) = 9(x -y)

The tens digit is twice the ones digit, so we have ...

  x = 2y

Substituting in the difference equation, we have ...

  27 = 9(x -y)

  3 = (2y -y) = y . . . . . divide by 9, substitute for x

  x = 2(3) = 6

The number is 10x+y = 63.