3 years ago (j-3 and s-3) jake was 2 times sister (j-3)=2(s-3) find s
distribute 2(s-3)=2s-6
now we have j-3=2s-6 we have j=5+s subsitute that (subsitute 5+s for j) 5+s-3=2s-6 add like terms s+2=2s-6 subtract s from both sides 2=s-6 add 6 to both sides 8=s his sister is 8 yeasr old