Let Jason be x years old.
Omar is 3 times older than Jason, so he will be 3x years old.
Henry is 5 years older than Jason, so he will be x + 5 years old.
Since their total age is 80, we have:
x + 3x + (x + 5) = 80
5x + 5 = 80
5x = 80 - 5
5x = 75
x = 75 / 5
x = 15
Jason's age = x = 15 years old
Omar's age = 3x = 3(15) = 45 years old
Henry's age = x + 5 = 15 + 5 = 20 years old