In a service station, five tasks – Body Wash, Brake Checking, Engine Tuning, Interior Wash and Wheel Alignment – had to be performed on a vehicle on a particular day. The order in which the five tasks should be performed was fixed. The time taken to finish each task was 10 minutes, 20 minutes, 30 minutes, 50 minutes and 80 minutes, not necessarily in the same order. The tasks should be performed one after the other and any task can be performed as soon as the previous task is completed. Further, each task can be performed by exactly one technician among Dev, Gaurav, Krish, Lalit and Raju, not necessarily in that order. On that particular day, each technician reached the service station at a different time. Any technician who reached the service station started working on his task immediately after he reached, providing all the preceding tasks, if any, were already complete. If not, he waited until all the tasks scheduled before his task were finished.

The following information is known about the details of the tasks:
i. Only one technician arrived by 10:00AM but he had to start his job at 11:20AM.

ii. Dev arrived at 12:00PM and started his task immediately.
iii. The first task to be finished did not take longer than 20 minutes.
iv. Interior Wash, which was the last task, was finished at 3:00PM.
v. Engine Tuning takes 30 minutes to complete, while Body Wash takes 50 minutes.
vi. Gaurav, who did not arrive first, performed Wheel Alignment and he was the third person to finish his task.
vii. Lalit was not the first person to arrive but finished his job before Dev, while Raju did not perform Interior Wash.

1. Which technician had to wait the longest to start his task after he arrived at the service station?

2. Which technician performed Body Wash?

3. How many technicians definitely did not have to wait to perform their tasks?

4. At what time did Krish arrive?


  1. The work gets completed at 3:00 PM while the total cycle of tasks took 190 mins. Still one of the technicians started his job at 11:20 AM.
    Please confirm if the information is correct.

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