Question

The number consists of 2 digits whose sum is 6.If 18 is added to the number ,the digits change their places.the number is

Answer 1

let the first digit be x
let the second digit be y

sum of those digits are 6
x + y = 6
if 18 is added to the number the digits change their places

xy + 18 = yx

here are your equations now solve it
hope it helps