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

2.5 - 2= 0.5 mln L of  the water  evaporated.

2.5 ---- 100%
0.5 ---- x %

x= (0.5*100)/2.5 = (5*100/25)=5*4=20%

20 % of the water evaporated.

Answer 2

2500000 2000000
___ = ________

100 X

100x2000000/2500000=x
X=80%
The answer is 80%