Is 4/16 a real number

Cindy uses 1-inch cubes to find the volume of a jewelry box shaped like a rectangular prism. she uses 780 cubes to completely fill the jewelry box with no gaps or overlaps. if the jewelry box is 13 inches long and 5 inches wide, how tall is cindy’s jewelry box?

Write an equation for the function that includes the points (2,100)and (3,100)

With finding limits of multi variable !