So all you need to do if find the min of the function:
f(x)=0.04x^3-4x^2-176x
f'(x)=0.12x^2-8x-176
The only zero for this is x=84.105 <---first
Plug this into f(x) to get f(84.105)=-19300 <---second
x|y............................
5|10
6|20
6|23
7|35
Answer:
4 kg
Step-by-step explanation:
so 1.6 * 4 is 6.4 so you just double check if you want
4 + 1.6 which is 1/4 of 6.4 will be 5.6 (matches with the question)
4 + (1.6*4) (indicates it's full) = 10.4( also Matches with the question)
there is another way by setting up an equation. let me know in comments if you want to see it that way