x 65 55 45 35
y 20 40 60 80
Let the cost of 1 kg of apples be x and that of 1 kg be y

So the algebraic representation can be as follows:
2x+y=160
4x+2y=300⇒2x+y=150

The situation can be represented graphically by plotting these two equations.

2x+y=160⇒y=160−2x
 x 70 60 50 40
 y=160−2x 20 40 60 80
2x+y=150⇒y=150−2x
 x 65 55 45 35
 y=150−2x 20 40 60 80
We can see that the lines do not intersect anywhere, i.e. they are parallel. Hence we can not arrive at a solution.