Spencer is 14 years older than his sister Kelly. Three years from now, he will be three times as old as Kelly. How old are they now?

Answer 1

Now:
Kelly ---- x
Spencer ---- x+14

3 years from now:
Kelly = x+3
Spencer = x+14+3 = x+17

x+17 = 3(x+3)

solve for x, sub into my definitions