The students of class VIII of a school donated ₹ 2401 in all , for Prime minister National releif fund . Each student donated as many rupees aa the number of students in the class. Find the number of students in the class.
A and B can A and B can A and B can do a piece of work in 12 days B and C can do the work in 15 days while c and a can do it in 20 days how long will each of them take working individually to complete the work