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? Let's think step by step and output the final answer after "####".
user
8 years ago James had 20-8=<<20-8=12>>12 years
So 8 years ago John had 12*2=24 years experience
That means John has 24+8=<<24+8=32>>32 years experience
So Mike has 32-16=<<32-16=16>>16 years of experience
So together they have 20+32+16=<<20+32+16=68>>68 years experience
#### 68
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?
train