let t = Tom's age
let g = Gary's age
let r = Reb's age
let s = Sam's age
:
tom is four less than twice gary's age.
t = 2g - 4
:
Gary's age
2g - 4 = t
2g = t + 4
g = t+4 over 2
:
rebecca is the youngest and she is two less than half gary's age after it was increased by three.
r = .5(g+3) -2
:
sam's age is the ratio of seven more than gary's age to eight less than gary's age.
s= (g+7) over (g-8)