the answer is that the student is right. take 1/3 of 16(b4h4) you 5.3 repeating
now take 1/3 of 64(b8h8) 21.3repeating. you divide 21.3 by 4 you get ^
double both height and base and the volume is 4 times as much.
-edit: yeah if you got a formula your all set remember that ^^