Multiple choice

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

  1. 420

  2. 320

  3. 450

  4. 500
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Let original expenditure be E for 35 students. New expenditure = E + 42 for 42 students. New average = (E+42)/42. Original average = E/35. Given: (E+42)/42 = E/35 - 1. Solving: E+42 = 42(E/35 - 1) = 6E/5 - 42. So E + 84 = 6E/5, giving 5E + 420 = 6E, thus E = 420.

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