Which bag amongst P Q R Sand T is the heaviest ? I. Bag Q is heavier than R and S. Bag T is heavier only than bag P. If Only three bags are lighter than R. The weight of bag Q is 50 kg which is 2 kg more than bag R.

Data sufficiency questions are designed to check your ability to analyse & categorise information based on underlying concepts rather than calculations. So you should try to observe -  analyse and to find linkages between various statements rather soing lengthy calculations.