Question 1155934
Little sister is now x
4 years ago she was x-4 and Bob was 2(x-4), or 2x-8
5 years from now she will be x+5 and Bob will be 2x+1, nine years later
2x+1-6=x+5
x=10
sister is 10 now
when she was 6 Bob was 12, so Bob is now 16

five years from now, he will be 21 and she 15, 6 years older than she