Answer:
Hello,
10 days
Step-by-step explanation:
60 étudiants dans un foyer ont assez de nourriture pour 30 jours. Si 20 étudiants supplémentaires rejoignent l'auberge après 10 jours, combien de temps durera la nourriture restante ?
Let say A the quantity of food
60 students in a hostel have food enough for 30 days ==> A=k*60*30
==> k=A/1800
Let say x the duration of the food.
60 students for x days + 20 students for (x-10) days =A
[tex]k*60*x+k*20*(x-10)=A\\[/tex]
[tex]\dfrac{A*60*x}{1800} +\dfrac{A*20*(x-10)}{1800} =A\\\\60x+20x-200=1800\\\\80x=1600\\\\x=20\\[/tex]
Duration for the 80 students: 20-10=10days
