Question

A part of monthly hostel charges is fixed and the remaining depends on the number of days one has taken food in mess. A student has to pay Rs. 1000, if she takes food for 20 days. write a linear equation which satisfies this data. also draw the graph for the same

Answer 1

Let the fixed part of monthly charge be x and the non - fixed part be y. If a be the number of days one has taken food in mess, we get :-
x + ay = Monthly Charge

According to question, a = 20 and monthly charge = 1000, we get :-
x + 20y = 1000
x = 1000 - 20y

Let y be 10, we get :-
x = 1000 - 20 x 10
= x = 1000 - 200  
= x = 800 [(800,10)]

Let y be 20, we get :-
x = 1000 - 20 x 20
= x = 1000 - 400
= x = 600 [(600,20)]
Thus the co-ordinates on the graph are (800,10) and (600,20).

Hope that helps !!