Answer:
20%
Step-by-step explanation:
Remember that percentages can be thought of as part over whole.
1. Find how much water evaporated.
[Starting amount]-[amount evaporated]=[amount left]
2,500,000 - x = 2,000,000
Solve for x
500,000-x=0
x=500,000.
This is how many liters were evaporated.
2. Set up a ratio to see what percentage was evaporated
[tex]\frac{500,000}{2,500,000}[/tex] = [tex]\frac{x}{100}[/tex]
x is the percentage you are looking for, and it is over one hundred because that is the "whole" of percentages: 100%. Remember that this is part over whole.
3. Simplify ratio and solve for x
[tex]\frac{500,000}{2,500,000}[/tex] simplifies to [tex]\frac{20}{100}[/tex] (divide top and bottom by the number that will get your denominator to be 100, which is 25,000)
Your answer is 20% since you have found what number goes in for x
