Answer
$\frac{5}{8}\gt\frac{11}{20}$
Work Step by Step
Find the LCD (lowest common denominator) of $8$ and $20$. List the multiple of 8 and 20.
8, 16, 24, 32, 40, 48, 56, 64, 72, 80, 88, 96, 104, 112, 120, 128
20, 40, 60, 80, 100, 120, 140, 160, 180, 200, 220.
The lowest common multiple of these numbers will be our denominator. The lowest common multiple is 40.
$\frac{5}{8}=\frac{5\times5}{8\times5}=\frac{25}{40}$
$\frac{11}{20}=\frac{11\times2}{20\times2}=\frac{22}{40}$
Since $\frac{25}{40}\gt\frac{22}{40}$; $\frac{5}{8}\gt\frac{11}{20}$