Question

A swimming pool had 2.5 million liters of water in it. Some water evaporated, and then the pool only had 2 million liters of water in it. What percent of the water evaporated?

Answer 1

First we need to find the liters of water that evaporated; we know that originally we had 2.5 million (2500000) liters of water, and after some of it evaporated we left with tow million liters (2000000), so:
2500000 - 2000000 = 500000 liters evaporated

Now, we can establish a rule of three ans solve for x to obtain the percentage of liters that evaporated:
2500000 -----> 100%
500000 -----> x%

`(2500000)/(500000) = (100)/(x)`

`x= ((500000)(100))/(2500000)`

`x=20`

We can conclude that 20% is the percentage of water that evaporated.

Answer 2

20% of the water evaporated. First, we must obtain the difference. The pool started with 2.5 million liters and ended with 2 million liters. 2.5 million - 2 million = 0.5 million. Next, we must identify what percentage of the water evaporated. We do that by taking the difference (0.5 million) and dividing by the original total (2.5 million). 0.2 million/2.5 million = 0.2 Lastly, we must convert to a percentage. Converting requires that we multiply by 100. 0.2 X 100 = 20%.