Question

9) In a two 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 the tens digit be x

Units digit be 2x

➟ Required number = 10x + 2x = 12x

On reversing the digits of the number,

T | O

2x |. x

Required number = 10(2x) + x = 21x

Also,

✪ According to the question ✰

If 27 is added to the original number, digits are reversed.

12x + 27 = 21x

⇒ 27 = 21x - 12x

⇒ 27 = 9x

⛇ Dividing by 9 on both sides ✸

x = 3

Therefore:

• Tens digit = x = 3
• Units digit = 2x = 6

The number is 36