Three solid cubes of lead，each with edges10 centimeters long，are melted together in a level，rectangular shaped pan．The base of the pan has inside dimensions of 20centimeters by 30 centimeters，and the pan is 15 centimeters deep．If the volume of the solid lead is approximately the same as thev olume of tile melted lead，approximately how many centimeters deep is the melted lead in the pan（）