Question Number 185705 by Mingma last updated on 26/Jan/23
Answered by mr W last updated on 26/Jan/23
$${s}=\frac{{n}−\mathrm{1}+{n}+{n}+\mathrm{1}}{\mathrm{2}}=\frac{\mathrm{3}{n}}{\mathrm{2}} \\ $$$$\overset{\_} {{r}}=\frac{{rs}}{{s}−{n}}=\frac{{r}}{\mathrm{1}−\frac{{n}}{{s}}}=\frac{{r}}{\mathrm{1}−\frac{\mathrm{2}{n}}{\mathrm{3}{n}}}=\mathrm{3}{r} \\ $$$$\frac{{r}}{\overset{\_} {{r}}}=\frac{\mathrm{1}}{\mathrm{3}}\:\checkmark \\ $$