To find the team's total yards gained, we need to add the yards gained on the first possession and subtract the yards lost on the next possession.
Yards gained on the first possession: 31 yards
Yards lost on the next possession: 16 yards
Total yards gained = Yards gained on the first possession - Yards lost on the next possession
Total yards gained = 31 yards - 16 yards
Total yards gained = 15 yards
So, the team's total yards gained is 15 yards.