Question

सर
R
51. एक छात्रावास में 100 छात्र थे। 20 छात्रों के बढ़ जाने से औसत व्यय 10 रु० घट गया,
जबकि मासिक आय 5000 रु० बढ़ गया। पहले छात्रों पर कितना व्यय होता था ?
(1) 20000 रु. (2) 31000 रु. (3) 40000 रु. (4) 30000​

Answer 1

Answer:

Rs 31000

Step-by-step explanation:

let the average expenditure of students be x

then:-

Total expenditure of 100 students =100x

Atq:-

when 20 students come the average expenditure

become Rs. 10 less and monthly expenditure become Rs. 5000 more.

then

Average expenditure = Rs (x-10)

Hense

120×( x- 10)=100x+5000

or. 120x-1200=100x+5000

or. 120x-100x=5000+1200

or. 20x=6200

or. x= 310

So:-

Total expenditure of 100 students

= 100×Rs. 310=Rs. 31000