Question

as a warden of the college hostel,you have noticed that some of the students residing in the hostel smoke and drink in the night .this is against the rules.write a memo to the students

Answer 1

Memo to all students residing in the hostels of D.AV. College,
                Viijawawda.

This is to request all boys residing in the college hostels to refrain from smoking and drinking in the hostel premises or elsewhere on the campus at any time during your stay. Besides being harmful to those indulging in smoking and drinking, these vices are a bad influence on the other residents.
It may please be noted that the college authority will take stern action if anyone is caught smoking or drinking. 
                                                                              
                                                                                Ravi Subrahmanyam
                                                                             Chief Warden - Hostels
                                                                                     D.A.V. College

Answer 2

sorry i don't know the proper format for a memo but here is the main context.

this is to inform all the students that many of you have been found consuming alcohol and smoking in the hostel premises . this is against the rules of the hostel and will not be tolerated by the authorities. further action will be taken against students who are found doing so . not only is this against the rules but also not good in any way for you students .

i hope this helps you...