A box of cereal measures 19.5 cm by 30 cm by 6.5 cm. It is filled to 80% capacity. A cereal bowl is hemispherical and measures 12 cm wide. How many bowls of cereal can be filled by one box of cereal?

Volume of cereal box=19.5*30*6.5=3802.5cc. The volume of cereal is 80% of this=0.8*3802.5=3042cc.

Volume of the cereal bowl is 2/3 (pi) r^3 (half the volume of a sphere 4/3 (pi) r^3) where r=radius=12/2=6cm. The volume is therefore 2/3 (pi) * 216=144 (pi) cc.

The number of full cereal bowls is 3042/144 (pi) = 21.125 / (pi) = 6.72. So 6 cereal bowls can be filled from the cereal in one cereal box.

The answer to this question is 6.