How many kilometers did Karan drive today ? It Karan correctly mentions that he drove less than 20 km but more than 14 km today. II. Karan's friend correctly mentions that Karan drove more than 10 km but less than 16 km today.

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.