By definition, $rho_"metal"="mass of metal"/"volume of metal"$
$=(800*g)/(33.0*cmxx46.0*cmxx48.0*cm)=0.0659*g*cm^-3$
And this is an IMPROBABLY undense metal. The LEAST dense metal, lithium, is approx. $0.5*g*cm^-3$...(at any rate this metal reacts with water)...the question is unreasonable and should not have been proposed.
Given the , the metal would float in water (if it didn't react with it!).