A suspension was prepared by mixing spherical gum grains with a density of 1.206 gcm- and a radius of 0.212 m and water with a density of 0.999 gcm- at 15C. Calculate Avagadro's constant (g= 9.8m s-, m= 10- m) since the number of particles determined microscopically in the same time at 5 m and 35 m heights from the base is 100 and 47, respectively.