Keisha needs 3/2 of potato per guest ( i.e one guest is equivalent to 3/2 potato)
Thus, for 15 guests
she needs;
[tex]\begin{gathered} 15\text{ }\times\frac{3}{2} \\ \frac{15\times3}{2}=\frac{45}{2} \\ 22\frac{1}{2} \end{gathered}[/tex]Keisha needs 45/2 potatoes for 15 guests
