The length of the banner if Amira uses all of the blue paint is 

Solution:
Given, Amira is painting a rectangular banner 
 yards wide on a wall in the cafeteria.
 yards wide on a wall in the cafeteria. 
The banner will have a blue background 
Amira has enough blue paint to cover 
 square yards of wall.
 square yards of wall. 
We have to find the length of the banner if Amira uses all of the blue paint. 
Now we know that, area of rectangle = length x width 

Hence, the length of the rectangle is 
 yards.
 yards.