Question 24328
Sarah = 4+4x
Denise = x 
Sarah in eight years = 8+4+4x
Denise in eight years = 8+x
Sum = 85


(8+4+4x)+(8+x)=85 Simplfy
5x+20=85
5x=65
x=13


4+4(13)=56


Hence, Sarah is 56 years old and Denise is 13 years old. 
Paul.