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.
