Answer
We can think of the system consisting of both teams and the rope. The friction from the ground exerts horizontal forces on the system. Whichever team is able to push harder on the ground will be able to win the contest.
Work Step by Step
We can think of the system consisting of both teams and the rope. The friction from the ground exerts horizontal forces on the system. Whichever team is able to push harder on the ground will be able to win the contest.