Answer:
The value of x is 7.5 in.
Explanation:
Consider the provided information.
Let the length of the box is x in, width 6 in and height is 5 in.
The Volume of the box is:



The surface area of rectangle is:
SA = 2[(length×width)+(width×height)+(length×height)]
SA = 2[(6×x)+(6×5)+(x×5)]
SA = 2[6x+30+5x]
SA = 2[11x+30]
It is given that surface area is equal to the value of the solids volume.
30x = 2[11x+30]
15x = 11x+30
4x = 30
x = 30/4
x = 7.5
Hence, the value of x is 7.5 in.