Question 1100778
The unclear part is how much is charged for the 4th kg. 
Does the 4th kg get the 15% discount or is it charged 240 or something else?
The first three kg would cost (3*240)*.85=612
If charging 240 for the 4th kg then the total is 612+240=852
If the 4th kg gets the 15% discount then the total is (4*240)*.85=816
if something else, then who knows.


Warning: I am still sick in bed. Double check my work.