Question

Suppose you have a bucket of sand containing 2.5 billion grains of sand (2.5 x 10 grains). Most of the grains of sand are white, but there are some brown grains mixed evenly throughout. Number If the concentration of brown sand is 2.0%, how many grains of brown sand are in the bucket? brown grains Number If the concentration of brown sand is 2.0 ppm I how many grains of brown sand are in the bucket?

Answer 1

Answer:

a. 5.0 x 10⁷ brown grains = 50 million

b. 5.0 x 10³ brown grains = 5000

Explanation:

The concentration of 2 % brown sand means we have for every 100 grains of sand 2 are brown.

We need to calculate the number of brown sand in the bucket as follows:

= 2.5 x 10⁹  billion grains of sand x  (2 brown grains/ 100 grains of sand)

= 5.0 x 10⁷ brown grains

Likewise if the concentration of brown sand is 2.0 ppm, it mean that we have 2 brown grain per every million grains of sand.

= 2.5 x 10⁹ billion grains of sand x ( 2.0 brown grains/10⁶ grains of sand )

= 5.0 x 10³ brown grains

The answers make sense since a concentration of 1 part per million is ten thousandths of  a 1 percent