Jack is 3 years older than Susan. The sum of their ages is 27. Find their ages.

Jack is 16.5 years old and Susan is 10.5 years old.

Step-by-step explanation:

27 divided by 2 is how old they would be if they were the same age. 27/2 is 13.5. 13.5 + 3 is how old Jack is and that is 16.5. 13.5 subtracted by 3 is Susan's age which is 10.5. We subtracted from her age so that the sum of their ages is still 27. 16.5 plus 10.5 is equal to 27.