Answer:
Length of square cut = 1.569 inches
Step-by-step explanation:
given data
Length of cardboard = 12 inches
Breadth of cardboard = 8 inches
solution
we will consider here side of the square = x
when we cutting out the square then there Length and breadth of candy box will be
Length of box = (12 - x - x)
Length of box = (12 - 2x) inches.
and
Breadth of box = (8 - x - x)
Breadth of box = (8 - 2x) inches.
and Height of candy box wil be = x inches
so
Volume of a cuboid = L × b × h .....................1
Volume of a cuboid = (12 - 2x) × (8 - 2x) × x
Volume of a cuboid = 96x - 40x² + 4x³
now we Differentiate with respect to x
V' = 96 - 80x + 12x²
and for maximum volume we put V' = 0
0 = 96 - 80x + 12x²
solve it we get
x = 5.097
x = 1.569
when x = 5.097 inches
Breadth of candy box = 8 - 10.194 = -2.194 inches
but we know breadth never be negative,
so we take
Length of square cut = 1.569 inches
