Question 316689
D=3X NOW.
S=X NOW.
IN 5 YEARS:
(3X+5)=2(X+5)
3X+5=2X+10
3X-2X=10-5
X=5 SAM'S AGE NOW.
D=3*5=15 YEARS OLD NOW.
PROOF:
(3*5+5)=2(5+5)
15+5=2*10
20=20 
IN 5 YEARS DAN WILL BE 15+5=20 YEARS OLD..
IN 5 YEARS SAM WILL BE  5+5=10 YEARS OLD.