In a hostel there were 100 students. To accommodate 20 more students the average is decreased by rupees 5. But total expenditure increased…

Rs.5400

100x + 400 = 12(x – 5)

x = 50

100 * 50 + 400 = 5400

let, x-average

y-total expenditure

then

y=100x------(1)

when students are increased by 20,

average decreases by 5

total expenditure is increased by 400



=> y+400=(x-5)120-----(2)



solving (1),(2)

x=10,y=5000

hence present total expenditure is 5400/-