step [tex] 1 [/tex]
Determine the total amount of fencing used by Alan
[tex] 5.9+10.3=16.2\ yards [/tex]
step [tex] 2 [/tex]
Determine the remaining amount of fence
Subtract [tex] 16.2 [/tex] from [tex] 20 [/tex]
[tex] 20-16.2=3.8\ yards [/tex]
step [tex] 3 [/tex]
convert the amount remaining as a fraction in simplest form
[tex] 3.8= 3+0.8 =3+\frac{8}{10} = 3\frac{4}{5} \ yards [/tex]
therefore
the answer is
[tex] 3\frac{4}{5} \ yards [/tex]