Question

The digit in the ones place of a number
is twice the digit in its tens place. If 9 is
added to the number, the digits of the
sum obtained are reverse of those of the
number. Find the number.​

Answer 1

Answer :-

12

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Given :-

• The digits in the ones place of a number is twice the digit in it's tens place.

• If 9 is added to the number, the digits of the sum obtained are reverse of those number.

To Find :-

• That number.

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Solution :-

Let tens digit be x

one's digit = 2x

Original number = 10x + 2x = 12x

Reversed number = x + 2x × 10 => 21x

A/q

12x + 9 = 21x

=> 9 = 21x - 12x

=> 9x = 9

=> x = 9/9

=> x = 1

So,

Ten's place, x = 1

one's place, 2x = 2 × 1 = 2

Hence, the number is 12

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