Question

the tens digit of a 2 digit number is twice of its unit digit .on reversing the digits the number formed is 27 less than the original number .find the original number​

Answer 1

The tens digit of a 2 digit number is twice of its unit digit.

On reversing the digits the number formed is 27 less than the original number.

Now, to find the answer

Let the digit in units and tens place be x and y.

then the number is y+10x

When the digits are reversed, the number is x+10y.

By the given conditions,

• y = 2x... ...(i)
• y + 10x = x + 10y - 27
• or 2x + 10x = x + 10 × 2x - 27 (using i)
• or 12x = x + 20x - 27
• or 21x - 12x = 27
• or 9x = 27
• or x = 3

putting x = 3 in (i) we get,

• y = 2 × 3
• or y = 6

Thus, the original number is

• y + 10x
• = 6 + 10 × 3
• = 6 + 30
• = 36.