There were 42 students in a hostel. Due to admission of 13 new students, expense of the mess increased by ₹30 per day, while per day expenditure per student is reduced by 3. What was the original expenditure of the mess per day?

₹630

Let the original expenditure per student = x

Now ATQ,

⇒ 55 (x - 3) = 42x + 30

(After adding 13 students, total expense of mess increased by Rs. 30 & per student expense is decreased by Rs. 3)

After solving, x = 15

Original expenditure of mess per day = 42x

                                                           = 42 x 15 = 630