Question

There were 35 students in a hostel. Due to the admission of 7 more students, the expenses of the mess were increased by rs. 42 per day, while the average expenditure per head diminished by re. 1 . What was the original expenditure of the mess?

Answer 1

let rate of each students be x .for 35 students its 35*x .
now on total of 42 students rate of each one becomes x-1 total expenses now will be 42(x-1).
now ,
42(x-1)-35x=42.
x=12