Question

In a two digit number, digit at the tens place is twice the digit at units place. If the number obtained by interchanging the digits is added to the original umber, the sum is 66. Find the number.

• A. 62
• B. 24
• C. 42
• D. 26

Answer 1

The correct option is C 42

Let x be the number at the units place and 2x is the number at the tens place.
Two digit number $=10\times 2x+x$
On interchanging $=10\times x+2x$
According to the conditions,
$10+2x+20x+x=66$
On Solving we get,
$x=2$
Two digit number $=10\times 2x+x=42.$