How many students from the class secured First Class ? I. The number of students securing First Class was equal to the number of students failed and was one third of the number of students passed in the class of 120 students. II. 1/4 th of the girls i. e. 10 and 1/4th of the boys secured 1st class in the class of 120 students.

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.