If the concentration of brown sand is 2.0 ppm, how many grains of brown sand are in the bucket?

I believe the complete given is that the bucket of sand contains 9.5 billion grains of sand. That is:

bucket = 9,500,000,000 grains

and the concentration of brown sand is 2 ppm:

concentration brown sand = 2 / 1,000,000

Therefore:

brown sand = 9,500,000,000 * (2 / 1,000,000)

brown sand = 19,000 grains