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Question
In a two digit number, the unit’s digit is twice the ten’s digit. If 27 is added to the number, the digit interchange their places. Find the number.
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Solution
Let ten's digit = x
Unit's digit = 2x
Required number
= 10x + 2x
= 12x
On interchanging the digit's
Number formed
= 10 (2x) + x
= 21x
According given condition
12x + 27 = 21x
27 = 21x - 12x
27 = 9x
∴ x = `(27)/(9)`
x = 3
∴ Required number
= 12 x 3
= 36.
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