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Approximately 2.5 percent of the total volume of water on Earth is in the form of freshwater. Of this freshwater, approximately 70 percent is in the form of surface water in rivers, lakes, ice, and permanent snow. The remaining 30 percent is stored underground in the form of groundwater.
Select for % of total volume of water represented by surface water the approximate percent of Earth's total water volume represented by freshwater in the form of surface water, and select for % of total volume of water represented by groundwater the approximate percentage of Earth's total water volume represented by groundwater, according to the information provided. Make only two selections, one in each column.
0.75
1.75
2.5
3
5.5
This is a percentage breakdown problem, so we'll use a simple flow diagram to show how the total water volume is divided:
Total Water on Earth (100%)
|
├── Freshwater (2.5%)
| |
| ├── Surface Water (70% of freshwater)
| └── Groundwater (30% of freshwater)
|
└── Other Water (97.5% - saltwater, etc.)
Let's make this concrete by assuming Earth has 100 units of total water:
We need to find:
Key insight: The question asks for percentages of TOTAL water, not percentages of freshwater. We need to calculate what portion of Earth's total water each type represents.
Surface water = 70% of freshwater
Surface water = \(0.70 \times 2.5\% = 1.75\%\) of total water
Groundwater = 30% of freshwater
Groundwater = \(0.30 \times 2.5\% = 0.75\%\) of total water
Let's verify our calculations add up correctly:
Final Answer:
Our calculations show that surface water represents 1.75% of Earth's total water volume, while groundwater represents 0.75% of the total.