to use a seive to seperatesand and rice seeds, what should be the size of the holes os the seivein comparison to the size of sand particles and rice seeds

Sieve separation is used to separate different size components of a mixture. The sieve used to separate sand particles and rice seeds should be such that it passes sand through its holes but the rice seeds cannot pass through them. The size of holes should be greater than the size of sand particles but less than the size of rice seeds.