For this case, the first thing we must do is define variables:
 x: Jane's age
 y: Helen's age
 By writing the system of equations we have:
 y = x + 8
 y-20 = 3 (x-20)
 Solving the system we have:
 x = 24
 y = 32
 Answer:
 Jane is 24 years old
 Helen is 32 years old
 the equation for Jane would look like:
 x + 8 = 3 (x-20) + 20