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