Answer: The equation would NOT help us solve for the length and width of the classroom is "[tex]x + 2y = 90[/tex]".
Step-by-step explanation:
Let y be the width of the rectangular classroom floor and x be the length of the rectangular classroom floor .
Given ,
The perimeter of a rectangular classroom floor is 90 feet.
The length of the floor is twice the width.
i.e. Length =2 (width)
i.e. x= 2y ..(i)
Also, perimeter = 2(length+width)
[tex]i.e. 2(x+y)=90\\\\\Rightarrow\ 2x+2y=90[/tex]
When we put value of x from (i), we get
[tex]2(2y) + 2y = 90[/tex]
Hence, the equation would NOT help us solve for the length and width of the classroom is "[tex]x + 2y = 90[/tex]".