Question

please answer this stepwise.

Answer 1

here is your sol check it....

Answer 2

Let fixed charge = P 
      the cost of food per day = Q
A/C to question,
                    for student A
 P + 20Q = 1000------------------(1)
                    for student B
 P +26Q = 1180---------------------(2)

solve eqns (1) and (2)
  6Q = 180 ,  Q = 30 put in equation (1) 
p =400

hence fixed charge = 400 Rs 
         cost food per day = 30 Rs