Question

serenity is 13 years old than chase. the sum of their ages is 27. how old are they?

Answer 1

let
x - chase
x + 13 - serenity

equation:
x + x + 13 = 27

Solution:
x + x + 13 = 27
2x + 13 = 27
2x = 27 - 13
2x = 14
x=7

Therefore, chase is 7 years old and serenity is 20 years old.

Answer 2

let the unit digit be x
let the tens digit be 4x

original number: 10(4x) + x = 41x
number reversed: 10x + 4x = 14x

41x + 14x = 110
55x = 110
x = 2

the original number is 84

try switching my definition and see what you get