Answer:
of square should be cut out of each corner to create a box with the largest volume.
Step-by-step explanation:
Given: Dimension of cardboard= 16 x 30“.
As per the dimension given, we know Lenght is 30 inches and width is 16 inches. Also the cardboard has 4 corners which should be cut out.
Lets assume the cut out size of each corner be "x".
∴ Size of cardboard after 4 corner will be cut out is:
Length (l)= 
Width (w)= 
Height (h)= 
Now, finding the volume of box after 4 corner been cut out.
Formula; Volume (v)= 
Volume(v)= 
Using distributive property of multiplication
⇒ Volume(v)= 
Next using differentiative method to find box largest volume, we will have 

Differentiating the value
⇒
taking out 12 as common in the equation and subtituting the value.
⇒ 
solving quadratic equation inside the parenthesis.
⇒
=0
Dividing 12 on both side
⇒
= 0
We can again take common as (x-12).
⇒
=0
∴
We have two value for x, which is 
12 is invalid as, w= 
∴ 24 inches can not be cut out of 16 inches width.
Hence, the cut out size from cardboard is 
Now, subtituting the value of x to find volume of the box.
Volume(v)= 
⇒ Volume(v)= 
⇒ Volume(v)= 
∴ Volume(v)= 725.93 inches³