Indian Institute of Foreign Trade 2012 Solved Paper

Question : 36 of 128

Marks: +1, -0

At a reputed Engineering College in India, total expenses of a trimester are partly fixed and partly varying linearly with the number of students. The average expense per student is Rs.400 when there are 20 students and Rs.300 when there are 40 students. When there are 80 students, what is the average expense per student?

Rs.250
Rs.300
Rs.330
Rs.350

Validate

Solution:

Let the total fees = T, the fixed fees = F, the number of students = n and let x be the varying fees.
Thus, T = F + nx
Given, when n = 20, T = 8000
Thus, 8000 = F + 20x
Also, when n = 40, T = 12000
Thus, 12000 = F + 40x
Solving we get F = 4000 and x = 200
Thus, the average rent when 80 students are staying

=4000/80+200=250

Rs
Hence, option A is the correct answer.

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