The answer is 800%
The original Volume is 15 (3*2.5*2)
The increased Volume is 120 (6*5*4)
An increase from 15 to 120 is 800% increase
Hello, and thanks for the question.The volume of a box (a rectangular prism) = length x breadth (width) x height. Height and depth would signify the same measurement. If, for example, you meant breadth equal to 2 feet. then the volume of the original box would be 3 ft. x 2 ft. x 2.5 ft. = 15 cubic ft. If the length and the breath are doubled and the height remains the same, then the volume of such a box would be 6 ft. x 4 ft. x 2.5 ft. = 60 cubic ft. -- an increase in volume of 300%.
Hope this helps!