[tex]\bf \begin{array}{ccll} feet&seconds\\ \cline{1-2} 4752&1\\ x&0.8 \end{array}\implies \cfrac{4752}{x}=\cfrac{1}{0.8}\implies 3801.6=x\implies \stackrel{\textit{rounded up}}{3802=x}[/tex]
so, we can conclude that since the wave went and came back in 0.8 seconds, it travelled the distance of 3802 feet, however that's the whole trip, we want to know how far the object is, and that'd be only the distance it took on its way forth, namely half the trip, namely 3802/2 = 1901.
