Question

In a 2-digit number, digit. in units place is twice
the digit in tens place. If 27 is added to it,
digits are reversed. Find the number ?​

Answer 1

• Let one's digit number be M and ten's digit number be N.

Original number = 10N + M

» In a 2-digit number, digit in units place is twice the digit in tens place.

According to question;

=> M = 2N ______ (eq 1)

» If 27 is added to it, digits are reversed.

According to question;

Revered number = 10M + N

=> 10M + N = 10N + M + 27

=> 10M - M + N - 10N = 27

=> 9M - 9N = 27

=> M - N = 3

=> (2N) - N = 3 [From (eq 1)]

=> 2N - N = 3

=> N = 3

Put value of N in (eq 1)

=> M = 2(3)

=> M = 6

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Number = 10N + M

Now put N and M values above.

=> 10(3) + 6

=> 30 + 6

=> 36

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Number = 36

_________ [ ANSWER ]

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