James has 20 years of experience. 8 years ago John had twice as much experience as James. Mike started when John had 16 years of experience. What is their combined experience? Think carefully first, then make a decision:
8 years ago James had 20 - 8 = 12 years. So 8 years ago John had 12 * 2 = 24 years experience. That means John has 24 + 8 = 32 years experience. So Mike has 32 - 16 = 16 years of experience. So together they have 20 + 32 + 16 = 68 years experience. So, the answer is 68.