A group of college students had decided to complete a project in 10 days. As 2 students dropped out every day, the project got completed at the end of the 15th day. The number of students at the beginning of the project was:

The project was initially planned to be completed in 10 days.

2 Students dropped out every day.

The project got completed on the 15th day instead.

Every day, the number of students decreases by 2.

The amount of work done each day is proportional to the number of students working on that day.

Total work remains the same, whether it is completed in 10 days or 15 days.

Solution: ​

Thus, the number of the students at beginning is 42.