diameter of marble = 1.4 cm
radius = 1.4/2 = 0.7 cm
volume of 1 marble = [tex] \frac{4}{3} \pi r^3 = \frac{4}{3} \times \pi \times (0.7)^3[/tex]
let number of marbles required = n
base diameter of beaker = 7cm
radius = 7/2 = 3.5 cm
height rise in water = 56 cm
volume change = volume of n marbles
[tex] \pi r^2h=n \times \frac{4}{3} \times \pi \times (0.7)^3\\ \\n= \frac{ \pi \times 3.5^2 \times 56}{(4/3) \times \pi \times 0.7^3} = \frac{3.5^2 \times 56 \times 3}{4 \times 0.7^3} =1500[/tex]
So 1500 marbles should be dropped.
