In a hostel of 100 students, provision was sufficient for 30 days. after one week some more students were admitted ,and the provision was consumed 3 days earlier. find the number of students newly admitted.

Number of days for which the provisions would last initially = 30
The number of days for which the
provisions would last after new students joined = (30 - 3) days
                                                                            = 27 days
So the number of students for which the provisions would last for 30 days = 100
Then
The number of students for which the provision would last for 1 day = (100/30)
                                                                                                                 = 10/3
So
The number of students for which the provision would last for 27 days = (10/3) * 27
                                                                                                                 = 90
So
The number of students that were admitted later = 100 -90
                                                                               = 10
So 10 students were admitted after one week.