Answer :
Volume of big box :
[tex]V=10\times 15\times 50\ ft^3\\\\V=7500\ ft^3[/tex]
Volume of small box :
[tex]v=15\times 15\times 25\ inch^3\\\\v=5625\ inch^3[/tex]
Space left in big box :
V' = V - 135
V' = 7500 - 135 ft³
V' = 7365 ft³
No of boxes that can fit :
[tex]n=\dfrac{7365\times 12^3}{5625}\\\\n=2262.528[/tex]
Therefore, the number of boxes are approximately 2266.
Hence, this is the required solution.