There were 35 students in a hostel. Due to the admission of 7 new students, the expenses of mess were increased by 42 per day while the average expenditure per head diminished by 1. What was the original expenditure of the mess?  Choose the correct choice
A) 400	B) 400	C) 445	D) 465	E) none of the above

Rationale: let the original average expenditure be ` x . then , 42 ( x – 1 ) – 35 x = 42 ⇔ 7 x = 84 ⇒ x = 12 . ∴ original expenditure = ( 35 × 12 ) = 420 . answer b
Answer: B