Givem:
The first board is 4 feet 8 inches long.
The second board is 3 feet 5 inches long.
The third board is 4 feet 4 inches long.
[tex]\begin{gathered} \text{Total length of the walkway=4 ft 8in.+3 ft 5in.+4ft 4in.} \\ =12\text{ feet }5\text{ inches} \end{gathered}[/tex]