let volume of sphere =V=S+H where H is hollow part's volume and S is volume of the metallic part or wateva.. now mass of sphere=S*(rho of solidpart)*g + H*0*g =5Sg now in water force upward is V(rhowater)*g=Vg as weight in water becomes 1/2 original.. upward force=half the weight so Vg=(5Sg)/2 so V=(5/2)S S=V-H so V=(5/2)(V-H) so H=3/5V hence fraction of hollow part is 0.6
Moderation Team
![[Post New]](/templates/default/images/icon_minipost_new.gif){kind=icon}
![[Up]](/templates/default/images/icon_up.gif "[Up]"){kind=icon}
297
