Question

if you gave 18 napkins to a table of 6 how many would you give to 15 people

Answer 1

$\bf \begin{array}{ccll} napkins&people\\ \cline{1-2} 18&6\\ x&15 \end{array}\implies \cfrac{18}{x}=\cfrac{6}{15}\implies \cfrac{18\cdot 15}{6}=x\implies 45=x$