Question

Suppose you have a bucket of sand containing 5.5 billion grains of sand ( 5.5×109 grains). Most of the grains of sand are white, but there are some brown grains mixed evenly throughout. If the concentration of brown sand is 2.0% , how many grains of brown sand are in the bucket?

Answer 1

Grains of brown sand are in the bucket are
`1.1* 10^8 grains`.

Explanation:

Total number sand grains in the bucket =
`5.5* 10^9 grain`

Concentration of brown sand grains = 2.0%

Number of brown brain in the bucket be x

`\%=\frac{\text{Brown sand grains}}{\text{Total sand grains}}* 100`

`2.0\%=(x)/(5.5* 10^9 grain)* 100`

`x=1.1* 10^8 grains`

Grains of brown sand are in the bucket are
`1.1* 10^8 grains`.

Answer 2

1.1×10^8

Explanation:

2% of 5.5 billion is ...

2×10^-2 × 5.5×10^9 = 11×10^7 = 1.1×10^8

About 1.1×10^8 grains of brown sand are in the bucket.