Tom is less than 10 years old. He is one half as old as Chris. In 8 years, Tom will be three-fourths as old as Chris. How old is Tom?
Tom's age now ---- x , where x < 10
Chris' age now = 2x
8 years from now:
Tom --- x+8
Chris --- 2x+8
x+8 = (3/4)(2x+8)
4x + 32 = 6x + 24
-2x = -8
x = 4