Mark, Tony, and Grant decided to eat a 72-inch sub in one sitting. They divided it so that Tony (the big eater) would eat 8 inches less than triple what Mark would eat. That left Grant with a portion that was 5 inches longer than Mark's portion. How big was each person's portion?
t = 3m-8
g = m+5
m+t+g = 72
m + 3m-8 + m+5 = 72
5m-3 = 72
5m = 75
m = 15
Mark: 15
Tony: 37
Grant: 20
------------
total: 72