Question

If about 1/40 of the earths water is fresh water. About 3/10 of the earths fresh water is ground water. What fraction of the earths water is ground water.

Answer 1

Answer: Ground water is 3/400 of earth's water

Explanation:

Let x represent earth's water,

F represent earth's fresh water, and

G represent earth's ground water.

The statement can then be expressed as follows:

About 1/40 of the earth's water is fresh water:

(1/40)x = F

About 3/10 of the earths fresh water is ground water:

Say: (3/10)F = G

=> (3/10)(1/40)x = G

(3/400)x = G

Therefore, ground water is 3/400 of the earth's water.

Answer 2

3/400

Explanation:

Let w represent earth's water

let f represent fresh water and let g represent ground water

`f = (1)/(40)w`

`g =(3)/(10)f = (3)/(10)((1)/(40)w)\\ \\g = (3)/(400)w`

Therefore, fraction of earth's water,w, that is ground water = 3/400