We are given that:
Area of rectangle is given by:
[tex] \implies\quad{\pmb{ \sf{Area = length\times width}} }[/tex]
Hence, putting the values in the formula:
[tex] \implies\quad \sf{ A = l\times w}[/tex]
[tex] \implies\quad \sf{ 30\sqrt{3750}=3\sqrt{250}\times w}[/tex]
[tex] \implies\quad \sf{3\sqrt{250}\times w = 30\sqrt{3750} }[/tex]
[tex] \implies\quad \sf{ w =\dfrac{30\sqrt{3750}}{3\sqrt{250}}}[/tex]
[tex] \implies\quad \sf{ w =10\dfrac{\sqrt{3750}}{\sqrt{250}}}[/tex]
[tex] \implies\quad \sf{ w = 10\times\sqrt{\dfrac{3750}{250}}}[/tex]
[tex] \implies\quad \underline{\underline{\pmb{\sf{ w =10\sqrt{15}}}}}[/tex]