N=50 because if he was 53 two years ago that means he is 55 today and if n+10 is how he will be in 5 years and he is 55 then he will be 60. N plus 10 equals his age in 5 years which is 60 so n equals 50 because 50 plus 10 equals 60 which is how old he will be in 5 years.