This problem is terribly botched!
Bob is three times as old as Jenny, who is five times as old
as Lou.
This means that Bob, who is x, is 15 times as old as Lou.
So if we kept everybody under 100 years old, Lou could only
be 1,2,3,4,5 or 6 now. which would make him 11,12,13,14,15,
or 16 in 10 years. So here are the only possibilities:
Lou
in
Bob 10 choice choice choice choice choice
Lou Jenny x years a) b) c) d) e)
1 5 15 11 1 8.5 7 3 1.1
2 10 30 12 2 16 12 6 2.3
3 15 45 13 3 23.5 17 9 2.5
4 20 60 14 4 31 22 12 4.6
5 25 75 15 5 38.5 27 15 5.8
6 30 90 16 6 46 32 18 8.1
If Bob is x=30, the correct choice will be c)
If Bob is x=75, the correct choice will be d)
But for Bob being any other age, all the choices are wrong.
This is a monstrosity of a problem, but I got my kicks by
analyzing it. lol
Edwin