x is sarah
y = vika
two equations:
x = y + 16
and
(x-4) = 2(y-4)
x - 4 = 2y - 8
x = 2y - 4
substitute this eqn into the top equation from before x = y + 16 for all x in it
2y - 4 = y + 16
y - 4 = 16
y = 20
find sarah using x = 2y - 4
x = 2(20) - 4
x = 40 - 4
x = 36
sarah is 36 years old and vika is 20 years old
