Question

After Don ate 1/8 of the pie and Ron ate 1/7 of the remainder of the pie, the other five friends divided the rest of the pie equally among themselves what percent of the original pie did each friend eat?

Answer 1

x = the whole pie.

well, Don ate (1/8)x, how much was it left?  $x -\cfrac{1}{8}x\implies \cfrac{x}{1} -\cfrac{x}{8}\implies \cfrac{8x-x}{8}\implies \cfrac{7x}{8}$

well, so that's the remainder.

Then Ron ate 1/7 of the remainder $\cfrac{7x}{8}\div 7\implies \cfrac{7x}{8}\div \cfrac{7}{1}\implies \cfrac{7x}{8}\cdot \cfrac{1}{7}\implies \cfrac{x}{8}$

well, how much is it left?  $\stackrel{\textit{Don leftover}}{\cfrac{7x}{8}}-\stackrel{\textit{Ron's bite}}{\cfrac{x}{8}}\implies \cfrac{6x}{8}\implies \cfrac{3x}{4}$

well, there are 5 friends how much did each one get from the whole pie?

$\cfrac{3x}{4}\div 5\implies \cfrac{3x}{4}\div \cfrac{5}{1}\implies \cfrac{3x}{4}\cdot \cfrac{1}{5}\implies \implies \cfrac{3x}{20}\implies \stackrel{\textit{each friend}}{\boxed{\cfrac{3}{20}x}}$