Question

The tens place digit of a two - digit number is twice the digit of unit place digit. The number obtained by interchanging the digits diminished the original number by 36. Find the number.

Answer 1

let the digit at unit place be x
so, digit at tens place = 2x
Number formed = 10(2x) + x = 20x + x = 21x

By interchanging digits,
digit at ones place = 2x
digit at tens place = x
Number formed = 10x + 2x = 12x

According to the question,

21x - 12x = 36
9x = 36
x = 36/9 = 4
x = 4

Original number = 84