There were 35 students in a hostel. If the number of students be increased by 7, the
expenditure on food increases by ` 42 per day while the average expenditure of students
is reduced by ` 1. What was the initial expenditure on food per day?

• Ans:- Initial expenditure = 420 and New Exp = 462
  Let the original average expenditure be Rs.x then,
  42(x - 1) = 35x + 42.........(bcz 1 rupee expenditure is reduced per student and we have total of 34+7=42 students )
  ⇒ 7x = 84
  ⇒ x = 12
  Therefore original expenditure = Rs.(35 × 12)=Rs.420.
  New Exp=420+42=462
• 6 years agoHelpfull: Yes(10) No(1)
• Lets proceed with method rule of three:
  students expense/day
  35 x
  35+7=42 x+42
  its a direct proportion
  hence
  35/42=x/x+42
  on solving
  x=210
• 6 years agoHelpfull: Yes(3) No(4)
• 210
  as the number of student increased by 7 the expenditure on food if increased by 42.
  so per student expenditure will be 42/7=6 per day
  so initially there were 35 students are present
  so food expenditure on them will be 35*6=210
• 6 years agoHelpfull: Yes(2) No(2)
• Let Avg Exp=x
  
  =>for 35 students=35x
  for 7 students=35x+42
  
  =>(35x+42)/42=1
  35x+42=42x-42
  =>7x=84
  =>x=12
  
  So, Total Exp=35*12=420
  New Exp=420+42=462
• 6 years agoHelpfull: Yes(1) No(1)
• initial average expenidture is X.
  Total expenditure = 35X.
  By question,
  35X+42 = (X - 1)*42
  35X + 42 = 42X - 42
  7X = 84
  X = Rs. 12
  So, Initial expenditure would be 12 *35 = Rs. 420
• 6 years agoHelpfull: Yes(1) No(1)
• 42(x - 1) = 35x + 42.
  ⇒ 7x = 84
  ⇒ x = 12
  Therefore original expenditure = Rs.(35 × 12)=Rs.420.
• 6 years agoHelpfull: Yes(0) No(1)