Question

sometimes in a game of tug of war . the team with more members loses the game. why does this happens?

Answer 1

This is because in a tug of war, technique, skills and stamina matter most than the number of people in the teams. If the team with the most people lack the skills of winning in a tug of war they will most likely be beaten by a smaller team with skills. 
The trick, rather skill, behind winning in a tug of war, is to use your weight and legs to pull the other team rather than using your arm. Getting a firm good grip on the ground and using your weight to pull the other team will help you beat the other team in case they lack these crucial techniques.