Hiring process consist of four round . 1) Written Online test 2) Telephonic interview 3) Case Study Interview 4) Principle Interview All the rounds are elimination one . First round i.e online test consist of four sections aptitude , english , reasoning and attention to details . Questions in the all the sections are easy but the time given for each question is less than a minute . Speed as well as accuracy plays an important role in order to get through this round .Duration of the exam is 78 mins . Each section has its individual time limit . Second round was hr round for around one hour . Questions that were asked is tell me about yourself . If you already working in some company they may ask why u want to leave that company , they can ask the engineers that why u want to enter in this field . he will also ask u 2-3 puzzles . The puzzles which he asked was one related to two egg and a 100 floor building and other was u are given 12 bulbs , there was one defective bulbs in it . Min trials required to find out the defective bulb using the weigh balance . Answer to both the question can be found out in internet . Third round was the case study round which is divided into 2 parts each of 30 mins duartion . In the first session u will be given a case related to some xyz pharmaceuticals company there is decrease in sales over year of time . u will be given some data Using that you have to answers the 8 questions in 30 min time . In the next 30 min time you have to explain how you arrive at the answers to one consultant of ZS .