???????????? yu hav vertikal cyliner with water init ?????????????
wen yu add 20 round marbels it kauz water tu go up how much ?????????
???????? marbel wide=1 cm ???????
volume av spheer=(4/3)pi*radius^3
radius=wide/2=0.5 cm
rad^3=(1/2)^3=1/8
(4/3)/8=1/6....so volume av 1 spheer =pi/6=0.5235987755982988