Question

the ones digitof a 2 -digit number is half of the tens digit.when the number is reserved.it is 27 less than the original number .what is original number?

Answer 1

Let the two digit number be 10x + y

$x = 2y$
$10y + x = 10x + y - 27 \\ x - y = 3$
on solving
$y = 3 \\ x = 6$
The number is 63