Answer: [tex]14\ ft[/tex]
Step-by-step explanation:
Given
Length of rectangle is [tex]6\ ft[/tex]
Perimeter must be greater than 40 ft
Suppose l and w be the length and width of the rectangle
[tex]\Rightarrow \text{Perimeter P=}2(l+w)\\\Rightarrow P\geq 40\\\Rightarrow 2(l+w)\geq40\\\Rightarrow l+w\geq20\\\Rightarrow w\geq20-6\\\Rightarrow w\geq14\ ft[/tex]
So, the smallest width can be [tex]14\ ft[/tex]