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In a hostel there were 100 students. To accommodate 20 more students the average is decreased by rupees 5. But total expenditure increased by Rs.400. Find the total expenditure of the hostel now?

Correct answer: C. Rs.5400

  • A. Rs.5000
  • B. Rs.4600
  • C. Rs.5400
  • D. Rs.2300

Explanation

Let the original average expenditure be Rs.x, so the original total is Rs.100x. After adding 20 students, the average is Rs.(x - 5) and the new total is Rs.100x + Rs.400; hence 120(x - 5) = 100x + 400, giving x = Rs.50. The new total is therefore Rs.100 x Rs.50 + Rs.400 = Rs.5,400. The likely mistake is choosing Rs.5,000, which is the original total rather than the increased total.

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