Question: Jenny is older than Charlie by five years, while Charlie is older than Bobby by three years. How old will Charlie be when Jenny becomes twice as old as Bobby? Think carefully first, then make a decision:
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 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. So the answer is 11.