Alright, let get started.
Kyle has a storage box having dimensions 2 ft long, 3 ft high and volume 12 cubic feet.
The formula for volume is =

Suppose the width is w so,


Dividing by 6 in both sides
w = 2 feet
Myla has a storage box that is 4 ft high and 2 feet long and volume 16 cubic feet.
Suppose the width is w hence


Dividing 8 in both sides
w = 2 feet
Hence the width of Kyle and Myla's boxes, both are 2 feet. : Answer
Hope it will help :)