If the amount on a certain principal in 3 years at 12% rate of interest compounded annually is Rs 12,000, what will be the amount (in Rs) after the 4th year?
There were 42 students in a hostel. Due to the admission of 13 new students, the expenses of the mess increase by Rs. 30 per day while the average expenditure per head diminished by Rs. 3. What was the original expenditure of the mess ?