Answer :
[tex]\begin{gathered} The\text{ recipe n}eeds \\ 2\frac{1}{2}\text{ Cup of sugar = }\frac{2}{5}\text{ of cup of floor} \\ x\text{ cup of Sugar = 1 cup of Floor} \\ By\text{ Cross multiplying} \\ \frac{2}{5}\text{ x }x\text{ = }2\frac{1}{2}\text{ x 1} \\ \frac{2x\text{ }}{5}\text{ = }\frac{5}{2} \\ x\text{ =}\frac{25}{4}\text{ = }6\frac{1}{4}\text{ Cups of floor} \end{gathered}[/tex]