Devaughn is 9 years younger than sydney. the sum of their ages is 45. what is sydneys age?

Sydney's age is 27 years of age. A way to do this is by subtracting 9 from 45 to get 36 and dividing it by 2 which gets you 18 and then adding 9 to that number since 18 is how old Devaughn is

X+x-9 = 45
2x-9 = 45
2x=54
x=27

Sydney is 27.