Question

In a two digit number, the digit at the unit's place is $1$ less than twice the digit at the ten's place. If the digit at unit's and ten's place are interchanged, the difference between the new and the original number is less than the original number by $20$. The original number is

• A. $59$
• B. $23$
• C. $35$
• D. $47$
• E. None of these

Answer 1

The correct option is D $47$

The ten's place number must be less than or equals to $5$, as given number is two digit number.
First condition,
The unit's place is $1$ less than twice the digit at the ten's place, such numbers are
$23,35,47$ and $59$
Now, take original number as $47$.
$74-47=27$
Here, $27$ is $20$ less than the original number $47$.