Let Sarah's present age =x
Let Vika's present age =y
Sarah's age exceeds Vika’s age by 16 years.

Four years ago,
Sarah's present age =x-4
Vika's present age =y-4
Four years ago, Sarah was twice as old as Vika was then.

Plugging the value of x from equation (1) in (2)



y=20
x=y+16 =20+16 = 36
Answer:
Sarah's present age =36
Vika's present age =16