Jenny is older than Charlie by 5 years who is older than Bobby by 3 years, so Jenny is older than Bobby by 5+3 = <<8=8>>8 years
Jenny will be twice as old as Bobby when he is 8*2 = 16 years old
Jenny is 5 years older than Charlie so when Jenny is 16, Charlie will be 16-5 = 11 years old
#### 11